21939546 has 16 divisors (see below), whose sum is σ = 44900064. Its totient is φ = 7143024.

The previous prime is 21939529. The next prime is 21939559. The reversal of 21939546 is 64593912.

It is a super-2 number, since 2×21939546² = 962687357372232, which contains 22 as substring.

It is a Curzon number.

It is an unprimeable number.

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, 42261 + ... + 42776.

It is an arithmetic number, because the mean of its divisors is an integer number (2806254).

Almost surely, 2^21939546 is an apocalyptic number.

21939546 is an abundant number, since it is smaller than the sum of its proper divisors (22960518).

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

21939546 is a wasteful number, since it uses less digits than its factorization.

21939546 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 85085.

The product of its digits is 58320, while the sum is 39.

The square root of 21939546 is about 4683.9669085082. The cubic root of 21939546 is about 279.9470393031.

The spelling of 21939546 in words is "twenty-one million, nine hundred thirty-nine thousand, five hundred forty-six".