20542136405 has 32 divisors (see below), whose sum is σ = 29876200704. Its totient is φ = 13236581376.

The previous prime is 20542136393. The next prime is 20542136497. The reversal of 20542136405 is 50463124502.

It is a cyclic number.

It is not a de Polignac number, because 20542136405 - 2¹⁸ = 20541874261 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 355739 + ... + 409431.

It is an arithmetic number, because the mean of its divisors is an integer number (933631272).

Almost surely, 2^20542136405 is an apocalyptic number.

It is an amenable number.

20542136405 is a deficient number, since it is larger than the sum of its proper divisors (9334064299).

20542136405 is a wasteful number, since it uses less digits than its factorization.

20542136405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54365.

The product of its (nonzero) digits is 28800, while the sum is 32.

The spelling of 20542136405 in words is "twenty billion, five hundred forty-two million, one hundred thirty-six thousand, four hundred five".