642739515 has 16 divisors (see below), whose sum is σ = 1121872896. Its totient is φ = 311631200.

The previous prime is 642739501. The next prime is 642739541. The reversal of 642739515 is 515937246.

It is not a de Polignac number, because 642739515 - 2⁷ = 642739387 is a prime.

It is a super-2 number, since 2×642739515² = 826228168284870450, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1947531 + ... + 1947860.

It is an arithmetic number, because the mean of its divisors is an integer number (70117056).

Almost surely, 2^642739515 is an apocalyptic number.

642739515 is a deficient number, since it is larger than the sum of its proper divisors (479133381).

642739515 is a wasteful number, since it uses less digits than its factorization.

642739515 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3895410.

The product of its digits is 226800, while the sum is 42.

The square root of 642739515 is about 25352.3078831100. The cubic root of 642739515 is about 863.0017311821.

The spelling of 642739515 in words is "six hundred forty-two million, seven hundred thirty-nine thousand, five hundred fifteen".