21359860 has 24 divisors (see below), whose sum is σ = 44956296. Its totient is φ = 8524800.

The previous prime is 21359851. The next prime is 21359861. The reversal of 21359860 is 6895312.

It can be written as a sum of positive squares in 4 ways, for example, as 620944 + 20738916 = 788^2 + 4554^2 .

It is a hoax number, since the sum of its digits (34) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21359861) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10960 + ... + 12760.

It is an arithmetic number, because the mean of its divisors is an integer number (1873179).

Almost surely, 2^21359860 is an apocalyptic number.

21359860 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21359860 is an abundant number, since it is smaller than the sum of its proper divisors (23596436).

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

21359860 is a wasteful number, since it uses less digits than its factorization.

21359860 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2403 (or 2401 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 34.

The square root of 21359860 is about 4621.6728573104. The cubic root of 21359860 is about 277.4594156486.

The spelling of 21359860 in words is "twenty-one million, three hundred fifty-nine thousand, eight hundred sixty".