791215981 has 2 divisors, whose sum is σ = 791215982. Its totient is φ = 791215980.

The previous prime is 791215967. The next prime is 791215987. The reversal of 791215981 is 189512197.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 787700356 + 3515625 = 28066^2 + 1875^2 .

It is a cyclic number.

It is not a de Polignac number, because 791215981 - 2⁵ = 791215949 is a prime.

It is a super-2 number, since 2×791215981² = 1252045457179584722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (791215987) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 395607990 + 395607991.

It is an arithmetic number, because the mean of its divisors is an integer number (395607991).

Almost surely, 2^791215981 is an apocalyptic number.

It is an amenable number.

791215981 is a deficient number, since it is larger than the sum of its proper divisors (1).

791215981 is an equidigital number, since it uses as much as digits as its factorization.

791215981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 45360, while the sum is 43.

The square root of 791215981 is about 28128.5616589260. The cubic root of 791215981 is about 924.9076045038.

The spelling of 791215981 in words is "seven hundred ninety-one million, two hundred fifteen thousand, nine hundred eighty-one".