21851902 has 16 divisors (see below), whose sum is σ = 34793712. Its totient is φ = 10257280.

The previous prime is 21851897. The next prime is 21851917. The reversal of 21851902 is 20915812.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 22752 + ... + 23692.

It is an arithmetic number, because the mean of its divisors is an integer number (2174607).

Almost surely, 2^21851902 is an apocalyptic number.

21851902 is a deficient number, since it is larger than the sum of its proper divisors (12941810).

21851902 is a wasteful number, since it uses less digits than its factorization.

21851902 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1643.

The product of its (nonzero) digits is 1440, while the sum is 28.

The square root of 21851902 is about 4674.6018012233. The cubic root of 21851902 is about 279.5737647499.

The spelling of 21851902 in words is "twenty-one million, eight hundred fifty-one thousand, nine hundred two".