1261752421 has 4 divisors (see below), whose sum is σ = 1302454144. Its totient is φ = 1221050700.

The previous prime is 1261752419. The next prime is 1261752433. The reversal of 1261752421 is 1242571621.

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.

It is a cyclic number.

It is not a de Polignac number, because 1261752421 - 2¹ = 1261752419 is a prime.

It is a super-2 number, since 2×1261752421² = 3184038343798722482, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (31), and also a Moran number because the ratio is a prime number: 40701691 = 1261752421 / (1 + 2 + 6 + 1 + 7 + 5 + 2 + 4 + 2 + 1).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1261752721) 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, 20350815 + ... + 20350876.

It is an arithmetic number, because the mean of its divisors is an integer number (325613536).

Almost surely, 2^1261752421 is an apocalyptic number.

It is an amenable number.

1261752421 is a deficient number, since it is larger than the sum of its proper divisors (40701723).

1261752421 is an equidigital number, since it uses as much as digits as its factorization.

1261752421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40701722.

The product of its digits is 6720, while the sum is 31.

The square root of 1261752421 is about 35521.1545561233. The cubic root of 1261752421 is about 1080.5827961624.

The spelling of 1261752421 in words is "one billion, two hundred sixty-one million, seven hundred fifty-two thousand, four hundred twenty-one".