20918455531 has 12 divisors (see below), whose sum is σ = 21643599600. Its totient is φ = 20216296800.

The previous prime is 20918455501. The next prime is 20918455601. The reversal of 20918455531 is 13555481902.

It is not a de Polignac number, because 20918455531 - 2¹¹ = 20918453483 is a prime.

It is a super-2 number, since 2×20918455531² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20918455501) 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, 152706 + ... + 255256.

It is an arithmetic number, because the mean of its divisors is an integer number (1803633300).

Almost surely, 2^20918455531 is an apocalyptic number.

20918455531 is a deficient number, since it is larger than the sum of its proper divisors (725144069).

20918455531 is a wasteful number, since it uses less digits than its factorization.

20918455531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 102774 (or 102737 counting only the distinct ones).

The product of its (nonzero) digits is 216000, while the sum is 43.

The spelling of 20918455531 in words is "twenty billion, nine hundred eighteen million, four hundred fifty-five thousand, five hundred thirty-one".