21150015646 has 4 divisors (see below), whose sum is σ = 31725023472. Its totient is φ = 10575007822.

The previous prime is 21150015637. The next prime is 21150015671. The reversal of 21150015646 is 64651005112.

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, 5287503910 + ... + 5287503913.

It is an arithmetic number, because the mean of its divisors is an integer number (7931255868).

Almost surely, 2^21150015646 is an apocalyptic number.

21150015646 is a deficient number, since it is larger than the sum of its proper divisors (10575007826).

21150015646 is a wasteful number, since it uses less digits than its factorization.

21150015646 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10575007825.

The product of its (nonzero) digits is 7200, while the sum is 31.

The spelling of 21150015646 in words is "twenty-one billion, one hundred fifty million, fifteen thousand, six hundred forty-six".