21956378158 has 128 divisors (see below), whose sum is σ = 40487610240. Its totient is φ = 8798699520.

The previous prime is 21956378117. The next prime is 21956378159. The reversal of 21956378158 is 85187365912.

It is a junction number, because it is equal to n+sod(n) for n = 21956378099 and 21956378108.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21956378159) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 160265466 + ... + 160265602.

It is an arithmetic number, because the mean of its divisors is an integer number (316309455).

Almost surely, 2^21956378158 is an apocalyptic number.

21956378158 is a deficient number, since it is larger than the sum of its proper divisors (18531232082).

21956378158 is a wasteful number, since it uses less digits than its factorization.

21956378158 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 422.

The product of its digits is 3628800, while the sum is 55.

The spelling of 21956378158 in words is "twenty-one billion, nine hundred fifty-six million, three hundred seventy-eight thousand, one hundred fifty-eight".