21761616 has 20 divisors (see below), whose sum is σ = 56217632. Its totient is φ = 7253856.

The previous prime is 21761543. The next prime is 21761617. The reversal of 21761616 is 61616712.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21761617) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 226636 + ... + 226731.

Almost surely, 2^21761616 is an apocalyptic number.

It is an amenable number.

21761616 is an abundant number, since it is smaller than the sum of its proper divisors (34456016).

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

21761616 is a wasteful number, since it uses less digits than its factorization.

21761616 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 453378 (or 453372 counting only the distinct ones).

The product of its digits is 3024, while the sum is 30.

The square root of 21761616 is about 4664.9347262314. The cubic root of 21761616 is about 279.1881928105.

The spelling of 21761616 in words is "twenty-one million, seven hundred sixty-one thousand, six hundred sixteen".