1157977921 has 4 divisors (see below), whose sum is σ = 1158466644. Its totient is φ = 1157489200.

The previous prime is 1157977907. The next prime is 1157977927. The reversal of 1157977921 is 1297797511.

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

It can be written as a sum of positive squares in 2 ways, for example, as 289850625 + 868127296 = 17025^2 + 29464^2 .

It is a cyclic number.

It is not a de Polignac number, because 1157977921 - 2⁵ = 1157977889 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1157977927) 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, 240790 + ... + 245551.

It is an arithmetic number, because the mean of its divisors is an integer number (289616661).

Almost surely, 2^1157977921 is an apocalyptic number.

It is an amenable number.

1157977921 is a deficient number, since it is larger than the sum of its proper divisors (488723).

1157977921 is an equidigital number, since it uses as much as digits as its factorization.

1157977921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 488722.

The product of its digits is 277830, while the sum is 49.

The square root of 1157977921 is about 34029.0746421351. The cubic root of 1157977921 is about 1050.1066924086.

The spelling of 1157977921 in words is "one billion, one hundred fifty-seven million, nine hundred seventy-seven thousand, nine hundred twenty-one".