21515442902 has 4 divisors (see below), whose sum is σ = 32273164356. Its totient is φ = 10757721450.

The previous prime is 21515442863. The next prime is 21515442917. The reversal of 21515442902 is 20924451512.

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

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 as a sum of consecutive naturals, namely, 5378860724 + ... + 5378860727.

It is an arithmetic number, because the mean of its divisors is an integer number (8068291089).

Almost surely, 2^21515442902 is an apocalyptic number.

21515442902 is a deficient number, since it is larger than the sum of its proper divisors (10757721454).

21515442902 is a wasteful number, since it uses less digits than its factorization.

21515442902 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10757721453.

The product of its (nonzero) digits is 28800, while the sum is 35.

The spelling of 21515442902 in words is "twenty-one billion, five hundred fifteen million, four hundred forty-two thousand, nine hundred two".