21454947618 has 32 divisors (see below), whose sum is σ = 46221717696. Its totient is φ = 6599942208.

The previous prime is 21454947617. The next prime is 21454947643. The reversal of 21454947618 is 81674945412.

It is a super-2 number, since 2×21454947618² (a number of 21 digits) contains 22 as substring.

It is an alternating number because its digits alternate between even and odd.

It is not an unprimeable number, because it can be changed into a prime (21454947617) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 318996 + ... + 380352.

It is an arithmetic number, because the mean of its divisors is an integer number (1444428678).

Almost surely, 2^21454947618 is an apocalyptic number.

21454947618 is an abundant number, since it is smaller than the sum of its proper divisors (24766770078).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21454947618 is a wasteful number, since it uses less digits than its factorization.

21454947618 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65858.

The product of its digits is 1935360, while the sum is 51.

The spelling of 21454947618 in words is "twenty-one billion, four hundred fifty-four million, nine hundred forty-seven thousand, six hundred eighteen".