21916545 has 16 divisors (see below), whose sum is σ = 40076160. Its totient is φ = 10018944.

The previous prime is 21916537. The next prime is 21916549. The reversal of 21916545 is 54561912.

It is not a de Polignac number, because 21916545 - 2³ = 21916537 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21916549) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 104260 + ... + 104469.

It is an arithmetic number, because the mean of its divisors is an integer number (2504760).

Almost surely, 2^21916545 is an apocalyptic number.

It is an amenable number.

21916545 is a deficient number, since it is larger than the sum of its proper divisors (18159615).

21916545 is a wasteful number, since it uses less digits than its factorization.

21916545 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 208744.

The product of its digits is 10800, while the sum is 33.

The square root of 21916545 is about 4681.5109740339. The cubic root of 21916545 is about 279.8491747232.

The spelling of 21916545 in words is "twenty-one million, nine hundred sixteen thousand, five hundred forty-five".