21537910 has 16 divisors (see below), whose sum is σ = 38830176. Its totient is φ = 8601408.

The previous prime is 21537881. The next prime is 21537917. The reversal of 21537910 is 1973512.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21537917) 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 7 ways as a sum of consecutive naturals, for example, 6922 + ... + 9538.

It is an arithmetic number, because the mean of its divisors is an integer number (2426886).

Almost surely, 2^21537910 is an apocalyptic number.

21537910 is a deficient number, since it is larger than the sum of its proper divisors (17292266).

21537910 is a wasteful number, since it uses less digits than its factorization.

21537910 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3447.

The product of its (nonzero) digits is 1890, while the sum is 28.

The square root of 21537910 is about 4640.8953877458. The cubic root of 21537910 is about 278.2282255389.

The spelling of 21537910 in words is "twenty-one million, five hundred thirty-seven thousand, nine hundred ten".