21912550 has 24 divisors (see below), whose sum is σ = 44463672. Its totient is φ = 7968000.

The previous prime is 21912521. The next prime is 21912563. The reversal of 21912550 is 5521912.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 19371 + ... + 20470.

It is an arithmetic number, because the mean of its divisors is an integer number (1852653).

Almost surely, 2^21912550 is an apocalyptic number.

21912550 is an abundant number, since it is smaller than the sum of its proper divisors (22551122).

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

21912550 is a wasteful number, since it uses less digits than its factorization.

21912550 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39864 (or 39859 counting only the distinct ones).

The product of its (nonzero) digits is 900, while the sum is 25.

The square root of 21912550 is about 4681.0842761053. The cubic root of 21912550 is about 279.8321698320.

It can be divided in two parts, 219 and 12550, that added together give a square (12769 = 113²).

The spelling of 21912550 in words is "twenty-one million, nine hundred twelve thousand, five hundred fifty".