78561307644 has 24 divisors (see below), whose sum is σ = 191279706240. Its totient is φ = 25048532784.

The previous prime is 78561307637. The next prime is 78561307651. The reversal of 78561307644 is 44670316587.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (78561307637) and next prime (78561307651).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 142320934 + ... + 142321485.

It is an arithmetic number, because the mean of its divisors is an integer number (7969987760).

Almost surely, 2^78561307644 is an apocalyptic number.

It is an amenable number.

78561307644 is an abundant number, since it is smaller than the sum of its proper divisors (112718398596).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

78561307644 is a wasteful number, since it uses less digits than its factorization.

78561307644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 284642449 (or 284642447 counting only the distinct ones).

The product of its (nonzero) digits is 3386880, while the sum is 51.

The spelling of 78561307644 in words is "seventy-eight billion, five hundred sixty-one million, three hundred seven thousand, six hundred forty-four".