21851960 has 32 divisors (see below), whose sum is σ = 52950240. Its totient is φ = 8068224.

The previous prime is 21851959. The next prime is 21851981. The reversal of 21851960 is 6915812.

It is a congruent number.

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, 20492 + ... + 21531.

It is an arithmetic number, because the mean of its divisors is an integer number (1654695).

Almost surely, 2^21851960 is an apocalyptic number.

21851960 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21851960 is an abundant number, since it is smaller than the sum of its proper divisors (31098280).

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

21851960 is a wasteful number, since it uses less digits than its factorization.

21851960 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42047 (or 42043 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 32.

The square root of 21851960 is about 4674.6080049561. The cubic root of 21851960 is about 279.5740121009.

The spelling of 21851960 in words is "twenty-one million, eight hundred fifty-one thousand, nine hundred sixty".