20405512431 has 12 divisors (see below), whose sum is σ = 29508248952. Its totient is φ = 13588158096.

The previous prime is 20405512423. The next prime is 20405512483. The reversal of 20405512431 is 13421550402.

20405512431 is a `hidden beast` number, since 20 + 40 + 551 + 24 + 31 = 666.

It is not a de Polignac number, because 20405512431 - 2³ = 20405512423 is a prime.

It is a super-2 number, since 2×20405512431² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 20405512395 and 20405512404.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20405511431) 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, 1284741 + ... + 1300526.

It is an arithmetic number, because the mean of its divisors is an integer number (2459020746).

Almost surely, 2^20405512431 is an apocalyptic number.

20405512431 is a deficient number, since it is larger than the sum of its proper divisors (9102736521).

20405512431 is a wasteful number, since it uses less digits than its factorization.

20405512431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2586150 (or 2586147 counting only the distinct ones).

The product of its (nonzero) digits is 4800, while the sum is 27.

The spelling of 20405512431 in words is "twenty billion, four hundred five million, five hundred twelve thousand, four hundred thirty-one".