18356771820 has 48 divisors (see below), whose sum is σ = 51405758208. Its totient is φ = 4894491840.

The previous prime is 18356771809. The next prime is 18356771833. The reversal of 18356771820 is 2817765381.

It is a happy number.

It is a super-2 number, since 2×18356771820² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 18356771820.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 588825 + ... + 619215.

It is an arithmetic number, because the mean of its divisors is an integer number (1070953296).

Almost surely, 2^18356771820 is an apocalyptic number.

18356771820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18356771820 is an abundant number, since it is smaller than the sum of its proper divisors (33048986388).

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

18356771820 is a wasteful number, since it uses less digits than its factorization.

18356771820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40470 (or 40468 counting only the distinct ones).

The product of its (nonzero) digits is 564480, while the sum is 48.

The spelling of 18356771820 in words is "eighteen billion, three hundred fifty-six million, seven hundred seventy-one thousand, eight hundred twenty".