21606760 has 32 divisors (see below), whose sum is σ = 55560960. Its totient is φ = 7407936.

The previous prime is 21606757. The next prime is 21606787. The reversal of 21606760 is 6760612.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 38304 + ... + 38863.

It is an arithmetic number, because the mean of its divisors is an integer number (1736280).

Almost surely, 2^21606760 is an apocalyptic number.

21606760 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21606760 is an abundant number, since it is smaller than the sum of its proper divisors (33954200).

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

21606760 is a wasteful number, since it uses less digits than its factorization.

21606760 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 77185 (or 77181 counting only the distinct ones).

The product of its (nonzero) digits is 3024, while the sum is 28.

The square root of 21606760 is about 4648.3072187625. The cubic root of 21606760 is about 278.5243798944.

It can be divided in two parts, 21606 and 760, that added together give a triangular number (22366 = T₂₁₁).

The spelling of 21606760 in words is "twenty-one million, six hundred six thousand, seven hundred sixty".