21582773478 has 24 divisors (see below), whose sum is σ = 53443058448. Its totient is φ = 6166506672.

The previous prime is 21582773477. The next prime is 21582773489. The reversal of 21582773478 is 87437728512.

21582773478 is a `hidden beast` number, since 21 + 5 + 8 + 277 + 347 + 8 = 666.

It is a super-2 number, since 2×21582773478² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21582773477) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 85645801 + ... + 85646052.

It is an arithmetic number, because the mean of its divisors is an integer number (2226794102).

Almost surely, 2^21582773478 is an apocalyptic number.

21582773478 is an abundant number, since it is smaller than the sum of its proper divisors (31860284970).

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

21582773478 is a wasteful number, since it uses less digits than its factorization.

21582773478 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 171291868 (or 171291865 counting only the distinct ones).

The product of its digits is 5268480, while the sum is 54.

The spelling of 21582773478 in words is "twenty-one billion, five hundred eighty-two million, seven hundred seventy-three thousand, four hundred seventy-eight".