21961644 has 24 divisors (see below), whose sum is σ = 53941440. Its totient is φ = 6935184.

The previous prime is 21961627. The next prime is 21961697. The reversal of 21961644 is 44616912.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 47934 + ... + 48389.

It is an arithmetic number, because the mean of its divisors is an integer number (2247560).

Almost surely, 2^21961644 is an apocalyptic number.

It is an amenable number.

21961644 is an abundant number, since it is smaller than the sum of its proper divisors (31979796).

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

21961644 is a wasteful number, since it uses less digits than its factorization.

21961644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 96349 (or 96347 counting only the distinct ones).

The product of its digits is 10368, while the sum is 33.

The square root of 21961644 is about 4686.3252127867. The cubic root of 21961644 is about 280.0409973983.

The spelling of 21961644 in words is "twenty-one million, nine hundred sixty-one thousand, six hundred forty-four".