1245263621 has 4 divisors (see below), whose sum is σ = 1423158432. Its totient is φ = 1067368812.

The previous prime is 1245263587. The next prime is 1245263623. The reversal of 1245263621 is 1263625421.

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 an emirpimes, since its reverse is a distinct semiprime: 1263625421 = 977 ⋅1293373.

It is a cyclic number.

It is not a de Polignac number, because 1245263621 - 2²² = 1241069317 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1245263623) 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, 88947395 + ... + 88947408.

It is an arithmetic number, because the mean of its divisors is an integer number (355789608).

Almost surely, 2^1245263621 is an apocalyptic number.

It is an amenable number.

1245263621 is a deficient number, since it is larger than the sum of its proper divisors (177894811).

1245263621 is an equidigital number, since it uses as much as digits as its factorization.

1245263621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 177894810.

The product of its digits is 17280, while the sum is 32.

The square root of 1245263621 is about 35288.2929737328. The cubic root of 1245263621 is about 1075.8550603890.

The spelling of 1245263621 in words is "one billion, two hundred forty-five million, two hundred sixty-three thousand, six hundred twenty-one".