21502955 has 4 divisors (see below), whose sum is σ = 25803552. Its totient is φ = 17202360.

The previous prime is 21502939. The next prime is 21502961. The reversal of 21502955 is 55920512.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 21502955 - 2⁴ = 21502939 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2150291 + ... + 2150300.

It is an arithmetic number, because the mean of its divisors is an integer number (6450888).

Almost surely, 2^21502955 is an apocalyptic number.

21502955 is a deficient number, since it is larger than the sum of its proper divisors (4300597).

21502955 is an equidigital number, since it uses as much as digits as its factorization.

21502955 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4300596.

The product of its (nonzero) digits is 4500, while the sum is 29.

The square root of 21502955 is about 4637.1278826446. The cubic root of 21502955 is about 278.0776269943.

The spelling of 21502955 in words is "twenty-one million, five hundred two thousand, nine hundred fifty-five".