642015815 has 16 divisors (see below), whose sum is σ = 880963392. Its totient is φ = 439997184.

The previous prime is 642015811. The next prime is 642015821. The reversal of 642015815 is 518510246.

It is a cyclic number.

It is not a de Polignac number, because 642015815 - 2² = 642015811 is a prime.

It is a super-2 number, since 2×642015815² = 824368613420228450, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (642015811) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 79337 + ... + 87053.

It is an arithmetic number, because the mean of its divisors is an integer number (55060212).

Almost surely, 2^642015815 is an apocalyptic number.

642015815 is a deficient number, since it is larger than the sum of its proper divisors (238947577).

642015815 is a wasteful number, since it uses less digits than its factorization.

642015815 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10106.

The product of its (nonzero) digits is 9600, while the sum is 32.

The square root of 642015815 is about 25338.0310008493. The cubic root of 642015815 is about 862.6777072745.

The spelling of 642015815 in words is "six hundred forty-two million, fifteen thousand, eight hundred fifteen".