21056542 has 16 divisors (see below), whose sum is σ = 34195392. Its totient is φ = 9666720.

The previous prime is 21056537. The next prime is 21056543. The reversal of 21056542 is 24565012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21056543) 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, 3067 + ... + 7177.

It is an arithmetic number, because the mean of its divisors is an integer number (2137212).

Almost surely, 2^21056542 is an apocalyptic number.

21056542 is a deficient number, since it is larger than the sum of its proper divisors (13138850).

21056542 is a wasteful number, since it uses less digits than its factorization.

21056542 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4323.

The product of its (nonzero) digits is 2400, while the sum is 25.

The square root of 21056542 is about 4588.7407858802. The cubic root of 21056542 is about 276.1398069960.

The spelling of 21056542 in words is "twenty-one million, fifty-six thousand, five hundred forty-two".