21343746978 has 12 divisors (see below), whose sum is σ = 46244785158. Its totient is φ = 7114582320.

The previous prime is 21343746967. The next prime is 21343747049. The reversal of 21343746978 is 87964734312.

It can be written as a sum of positive squares in only one way, i.e., 18797232609 + 2546514369 = 137103^2 + 50463^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 592881843 + ... + 592881878.

Almost surely, 2^21343746978 is an apocalyptic number.

21343746978 is an abundant number, since it is smaller than the sum of its proper divisors (24901038180).

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

21343746978 is a wasteful number, since it uses less digits than its factorization.

21343746978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1185763729 (or 1185763726 counting only the distinct ones).

The product of its digits is 6096384, while the sum is 54.

The spelling of 21343746978 in words is "twenty-one billion, three hundred forty-three million, seven hundred forty-six thousand, nine hundred seventy-eight".