21154545956 has 12 divisors (see below), whose sum is σ = 37311955968. Its totient is φ = 10493987112.

The previous prime is 21154545953. The next prime is 21154546001. The reversal of 21154545956 is 65954545112.

It is a self number, because there is not a number n which added to its sum of digits gives 21154545956.

It is not an unprimeable number, because it can be changed into a prime (21154545953) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20820896 + ... + 20821911.

It is an arithmetic number, because the mean of its divisors is an integer number (3109329664).

Almost surely, 2^21154545956 is an apocalyptic number.

It is an amenable number.

21154545956 is a deficient number, since it is larger than the sum of its proper divisors (16157410012).

21154545956 is a wasteful number, since it uses less digits than its factorization.

21154545956 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41642938 (or 41642936 counting only the distinct ones).

The product of its digits is 1080000, while the sum is 47.

The spelling of 21154545956 in words is "twenty-one billion, one hundred fifty-four million, five hundred forty-five thousand, nine hundred fifty-six".