21865662 has 72 divisors (see below), whose sum is σ = 59380776. Its totient is φ = 5763744.

The previous prime is 21865661. The next prime is 21865687. The reversal of 21865662 is 26656812.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21865661) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 10513 + ... + 12419.

It is an arithmetic number, because the mean of its divisors is an integer number (824733).

Almost surely, 2^21865662 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21865662, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29690388).

21865662 is an abundant number, since it is smaller than the sum of its proper divisors (37515114).

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

21865662 is a wasteful number, since it uses less digits than its factorization.

21865662 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1942 (or 1932 counting only the distinct ones).

The product of its digits is 34560, while the sum is 36.

The square root of 21865662 is about 4676.0733527181. The cubic root of 21865662 is about 279.6324343617.

The spelling of 21865662 in words is "twenty-one million, eight hundred sixty-five thousand, six hundred sixty-two".