7921599157 has 4 divisors (see below), whose sum is σ = 8387575596. Its totient is φ = 7455622720.

The previous prime is 7921599109. The next prime is 7921599181. The reversal of 7921599157 is 7519951297.

It is a happy number.

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 7430267601 + 491331556 = 86199^2 + 22166^2 .

It is a cyclic number.

It is not a de Polignac number, because 7921599157 - 2²³ = 7913210549 is a prime.

It is a super-2 number, since 2×7921599157² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 7921599098 and 7921599107.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7921599457) 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, 232988194 + ... + 232988227.

It is an arithmetic number, because the mean of its divisors is an integer number (2096893899).

Almost surely, 2^7921599157 is an apocalyptic number.

It is an amenable number.

7921599157 is a deficient number, since it is larger than the sum of its proper divisors (465976439).

7921599157 is a wasteful number, since it uses less digits than its factorization.

7921599157 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 465976438.

The product of its digits is 1786050, while the sum is 55.

The square root of 7921599157 is about 89003.3659869109. The cubic root of 7921599157 is about 1993.4451367705.

The spelling of 7921599157 in words is "seven billion, nine hundred twenty-one million, five hundred ninety-nine thousand, one hundred fifty-seven".