20984431897 has 24 divisors (see below), whose sum is σ = 24867799488. Its totient is φ = 17589469920.

The previous prime is 20984431891. The next prime is 20984431903. The reversal of 20984431897 is 79813448902.

It is an interprime number because it is at equal distance from previous prime (20984431891) and next prime (20984431903).

It is not a de Polignac number, because 20984431897 - 2²³ = 20976043289 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20984431891) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1482588 + ... + 1496674.

It is an arithmetic number, because the mean of its divisors is an integer number (1036158312).

Almost surely, 2^20984431897 is an apocalyptic number.

It is an amenable number.

20984431897 is a deficient number, since it is larger than the sum of its proper divisors (3883367591).

20984431897 is a wasteful number, since it uses less digits than its factorization.

20984431897 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15069 (or 15058 counting only the distinct ones).

The product of its (nonzero) digits is 3483648, while the sum is 55.

The spelling of 20984431897 in words is "twenty billion, nine hundred eighty-four million, four hundred thirty-one thousand, eight hundred ninety-seven".