642915 has 48 divisors (see below), whose sum is σ = 1380288. Its totient is φ = 269568.

The previous prime is 642907. The next prime is 642931. The reversal of 642915 is 519246.

642915 is a `hidden beast` number, since 642 + 9 + 15 = 666.

It is not a de Polignac number, because 642915 - 2³ = 642907 is a prime.

It is a nialpdrome in base 15.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 642915.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 4017 + ... + 4173.

It is an arithmetic number, because the mean of its divisors is an integer number (28756).

2⁶⁴²⁹¹⁵ is an apocalyptic number.

642915 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

642915 is an abundant number, since it is smaller than the sum of its proper divisors (737373).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

642915 is a wasteful number, since it uses less digits than its factorization.

642915 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 188 (or 185 counting only the distinct ones).

The product of its digits is 2160, while the sum is 27.

The square root of 642915 is about 801.8198051932. The cubic root of 642915 is about 86.3080264852.

The spelling of 642915 in words is "six hundred forty-two thousand, nine hundred fifteen".