20978718554 has 8 divisors (see below), whose sum is σ = 32836255200. Its totient is φ = 10033300156.

The previous prime is 20978718517. The next prime is 20978718557. The reversal of 20978718554 is 45581787902.

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

It is a self number, because there is not a number n which added to its sum of digits gives 20978718554.

It is not an unprimeable number, because it can be changed into a prime (20978718557) 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, 228029504 + ... + 228029595.

It is an arithmetic number, because the mean of its divisors is an integer number (4104531900).

Almost surely, 2^20978718554 is an apocalyptic number.

20978718554 is a deficient number, since it is larger than the sum of its proper divisors (11857536646).

20978718554 is a wasteful number, since it uses less digits than its factorization.

20978718554 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 456059124.

The product of its (nonzero) digits is 5644800, while the sum is 56.

The spelling of 20978718554 in words is "twenty billion, nine hundred seventy-eight million, seven hundred eighteen thousand, five hundred fifty-four".