812557979 has 4 divisors (see below), whose sum is σ = 813180984. Its totient is φ = 811934976.

The previous prime is 812557969. The next prime is 812557981. The reversal of 812557979 is 979755218.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-812557979 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 812557979.

It is not an unprimeable number, because it can be changed into a prime (812557919) 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, 309542 + ... + 312155.

It is an arithmetic number, because the mean of its divisors is an integer number (203295246).

Almost surely, 2^812557979 is an apocalyptic number.

812557979 is a deficient number, since it is larger than the sum of its proper divisors (623005).

812557979 is a wasteful number, since it uses less digits than its factorization.

812557979 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 623004.

The product of its digits is 1587600, while the sum is 53.

The square root of 812557979 is about 28505.4026282738. The cubic root of 812557979 is about 933.1499842932.

The spelling of 812557979 in words is "eight hundred twelve million, five hundred fifty-seven thousand, nine hundred seventy-nine".