21310842 has 16 divisors (see below), whose sum is σ = 48710592. Its totient is φ = 6088800.

The previous prime is 21310841. The next prime is 21310847. The reversal of 21310842 is 24801312.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is not an unprimeable number, because it can be changed into a prime (21310841) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 253659 + ... + 253742.

It is an arithmetic number, because the mean of its divisors is an integer number (3044412).

Almost surely, 2^21310842 is an apocalyptic number.

21310842 is an abundant number, since it is smaller than the sum of its proper divisors (27399750).

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

21310842 is a wasteful number, since it uses less digits than its factorization.

21310842 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 507413.

The product of its (nonzero) digits is 384, while the sum is 21.

The square root of 21310842 is about 4616.3667531946. The cubic root of 21310842 is about 277.2470090957.

The spelling of 21310842 in words is "twenty-one million, three hundred ten thousand, eight hundred forty-two".