21502136 has 8 divisors (see below), whose sum is σ = 40316520. Its totient is φ = 10751064.

The previous prime is 21502123. The next prime is 21502157. The reversal of 21502136 is 63120512.

It is a tau number, because it is divible by the number of its divisors (8).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1343876 + ... + 1343891.

It is an arithmetic number, because the mean of its divisors is an integer number (5039565).

Almost surely, 2^21502136 is an apocalyptic number.

It is an amenable number.

21502136 is a deficient number, since it is larger than the sum of its proper divisors (18814384).

21502136 is a wasteful number, since it uses less digits than its factorization.

21502136 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2687773 (or 2687769 counting only the distinct ones).

The product of its (nonzero) digits is 360, while the sum is 20.

The square root of 21502136 is about 4637.0395728309. The cubic root of 21502136 is about 278.0740964956.

Adding to 21502136 its reverse (63120512), we get a palindrome (84622648).

The spelling of 21502136 in words is "twenty-one million, five hundred two thousand, one hundred thirty-six".