1252236421 has 4 divisors (see below), whose sum is σ = 1252318144. Its totient is φ = 1252154700.

The previous prime is 1252236361. The next prime is 1252236457. The reversal of 1252236421 is 1246322521.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 1246322521 = 6421 ⋅194101.

It is a 3-Lehmer number, since φ(1252236421) divides (1252236421-1)³.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1252236421 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1252236421.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1252233421) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10215 + ... + 51076.

It is an arithmetic number, because the mean of its divisors is an integer number (313079536).

It is a Poulet number, since it divides 2^1252236420-1.

Almost surely, 2^1252236421 is an apocalyptic number.

1252236421 is the 20431-st octagonal number.

It is an amenable number.

1252236421 is a deficient number, since it is larger than the sum of its proper divisors (81723).

1252236421 is an equidigital number, since it uses as much as digits as its factorization.

1252236421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 81722.

The product of its digits is 5760, while the sum is 28.

The square root of 1252236421 is about 35386.9526944607. The cubic root of 1252236421 is about 1077.8593919959.

Adding to 1252236421 its reverse (1246322521), we get a palindrome (2498558942).

The spelling of 1252236421 in words is "one billion, two hundred fifty-two million, two hundred thirty-six thousand, four hundred twenty-one".