21750756 has 12 divisors (see below), whose sum is σ = 50751792. Its totient is φ = 7250248.

The previous prime is 21750737. The next prime is 21750793. The reversal of 21750756 is 65705712.

It is a tau number, because it is divible by the number of its divisors (12).

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 906270 + ... + 906293.

It is an arithmetic number, because the mean of its divisors is an integer number (4229316).

Almost surely, 2^21750756 is an apocalyptic number.

It is an amenable number.

21750756 is an abundant number, since it is smaller than the sum of its proper divisors (29001036).

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

21750756 is a wasteful number, since it uses less digits than its factorization.

21750756 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1812570 (or 1812568 counting only the distinct ones).

The product of its (nonzero) digits is 14700, while the sum is 33.

The square root of 21750756 is about 4663.7705775477. The cubic root of 21750756 is about 279.1417427020.

The spelling of 21750756 in words is "twenty-one million, seven hundred fifty thousand, seven hundred fifty-six".