21159550 has 12 divisors (see below), whose sum is σ = 39356856. Its totient is φ = 8463800.

The previous prime is 21159539. The next prime is 21159587. The reversal of 21159550 is 5595112.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 211546 + ... + 211645.

It is an arithmetic number, because the mean of its divisors is an integer number (3279738).

Almost surely, 2^21159550 is an apocalyptic number.

21159550 is a deficient number, since it is larger than the sum of its proper divisors (18197306).

21159550 is a wasteful number, since it uses less digits than its factorization.

21159550 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 423203 (or 423198 counting only the distinct ones).

The product of its (nonzero) digits is 2250, while the sum is 28.

The square root of 21159550 is about 4599.9510866965. The cubic root of 21159550 is about 276.5893640582.

The spelling of 21159550 in words is "twenty-one million, one hundred fifty-nine thousand, five hundred fifty".