21534961 has 12 divisors (see below), whose sum is σ = 26370480. Its totient is φ = 17486280.

The previous prime is 21534911. The next prime is 21534967. The reversal of 21534961 is 16943512.

It is not a de Polignac number, because 21534961 - 2⁷ = 21534833 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21534967) 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 11 ways as a sum of consecutive naturals, for example, 10635 + ... + 12496.

It is an arithmetic number, because the mean of its divisors is an integer number (2197540).

Almost surely, 2^21534961 is an apocalyptic number.

It is an amenable number.

21534961 is a deficient number, since it is larger than the sum of its proper divisors (4835519).

21534961 is a wasteful number, since it uses less digits than its factorization.

21534961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23164 (or 23157 counting only the distinct ones).

The product of its digits is 6480, while the sum is 31.

The square root of 21534961 is about 4640.5776580077. The cubic root of 21534961 is about 278.2155264966.

The spelling of 21534961 in words is "twenty-one million, five hundred thirty-four thousand, nine hundred sixty-one".