21538250 has 32 divisors (see below), whose sum is σ = 40766544. Its totient is φ = 8520000.

The previous prime is 21538219. The next prime is 21538261. The reversal of 21538250 is 5283512.

It can be written as a sum of positive squares in 8 ways, for example, as 863041 + 20675209 = 929^2 + 4547^2 .

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 15 ways as a sum of consecutive naturals, for example, 24824 + ... + 25676.

Almost surely, 2^21538250 is an apocalyptic number.

21538250 is a deficient number, since it is larger than the sum of its proper divisors (19228294).

21538250 is a wasteful number, since it uses less digits than its factorization.

21538250 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 971 (or 961 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 26.

The square root of 21538250 is about 4640.9320184635. The cubic root of 21538250 is about 278.2296895791.

The spelling of 21538250 in words is "twenty-one million, five hundred thirty-eight thousand, two hundred fifty".