21015258 has 32 divisors (see below), whose sum is σ = 46180800. Its totient is φ = 6322560.

The previous prime is 21015257. The next prime is 21015263. The reversal of 21015258 is 85251012.

It is not an unprimeable number, because it can be changed into a prime (21015257) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8766 + ... + 10902.

It is an arithmetic number, because the mean of its divisors is an integer number (1443150).

Almost surely, 2^21015258 is an apocalyptic number.

21015258 is an abundant number, since it is smaller than the sum of its proper divisors (25165542).

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

21015258 is a wasteful number, since it uses less digits than its factorization.

21015258 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2302.

The product of its (nonzero) digits is 800, while the sum is 24.

The square root of 21015258 is about 4584.2401769541. The cubic root of 21015258 is about 275.9592199778.

The spelling of 21015258 in words is "twenty-one million, fifteen thousand, two hundred fifty-eight".