21053658 has 16 divisors (see below), whose sum is σ = 42641280. Its totient is φ = 6928896.

The previous prime is 21053657. The next prime is 21053663. The reversal of 21053658 is 85635012.

It is not an unprimeable number, because it can be changed into a prime (21053651) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21735 + ... + 22682.

It is an arithmetic number, because the mean of its divisors is an integer number (2665080).

Almost surely, 2^21053658 is an apocalyptic number.

21053658 is an abundant number, since it is smaller than the sum of its proper divisors (21587622).

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

21053658 is a wasteful number, since it uses less digits than its factorization.

21053658 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44501.

The product of its (nonzero) digits is 7200, while the sum is 30.

The square root of 21053658 is about 4588.4265276890. The cubic root of 21053658 is about 276.1271992980.

The spelling of 21053658 in words is "twenty-one million, fifty-three thousand, six hundred fifty-eight".