20456400399 has 16 divisors (see below), whose sum is σ = 28850963712. Its totient is φ = 12865963968.

The previous prime is 20456400389. The next prime is 20456400421. The reversal of 20456400399 is 99300465402.

It is not a de Polignac number, because 20456400399 - 2²⁰ = 20455351823 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20456400399.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20456400329) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2025577 + ... + 2035650.

It is an arithmetic number, because the mean of its divisors is an integer number (1803185232).

Almost surely, 2^20456400399 is an apocalyptic number.

20456400399 is a deficient number, since it is larger than the sum of its proper divisors (8394563313).

20456400399 is a wasteful number, since it uses less digits than its factorization.

20456400399 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4061326.

The product of its (nonzero) digits is 233280, while the sum is 42.

The spelling of 20456400399 in words is "twenty billion, four hundred fifty-six million, four hundred thousand, three hundred ninety-nine".