21875616 has 96 divisors (see below), whose sum is σ = 72938880. Its totient is φ = 6248448.

The previous prime is 21875611. The next prime is 21875629. The reversal of 21875616 is 61657812.

It is a tau number, because it is divible by the number of its divisors (96).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (21875611) 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, 4240 + ... + 7856.

It is an arithmetic number, because the mean of its divisors is an integer number (759780).

Almost surely, 2^21875616 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21875616, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36469440).

21875616 is an abundant number, since it is smaller than the sum of its proper divisors (51063264).

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

21875616 is a wasteful number, since it uses less digits than its factorization.

21875616 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3643 (or 3629 counting only the distinct ones).

The product of its digits is 20160, while the sum is 36.

The square root of 21875616 is about 4677.1375861738. The cubic root of 21875616 is about 279.6748606858.

The spelling of 21875616 in words is "twenty-one million, eight hundred seventy-five thousand, six hundred sixteen".