21215894618 has 8 divisors (see below), whose sum is σ = 31851022080. Its totient is φ = 10598887260.

The previous prime is 21215894597. The next prime is 21215894633. The reversal of 21215894618 is 81649851212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-2 number, since 2×21215894618² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4527098 + ... + 4531781.

It is an arithmetic number, because the mean of its divisors is an integer number (3981377760).

Almost surely, 2^21215894618 is an apocalyptic number.

21215894618 is a deficient number, since it is larger than the sum of its proper divisors (10635127462).

21215894618 is a wasteful number, since it uses less digits than its factorization.

21215894618 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9060052.

The product of its digits is 276480, while the sum is 47.

The spelling of 21215894618 in words is "twenty-one billion, two hundred fifteen million, eight hundred ninety-four thousand, six hundred eighteen".