20400514921 has 4 divisors (see below), whose sum is σ = 20466111744. Its totient is φ = 20334918100.

The previous prime is 20400514867. The next prime is 20400514933. The reversal of 20400514921 is 12941500402.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 12941500402 = 2 ⋅6470750201.

It is a cyclic number.

It is not a de Polignac number, because 20400514921 - 2⁷ = 20400514793 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20400514921.

It is not an unprimeable number, because it can be changed into a prime (20400514951) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 32797945 + ... + 32798566.

It is an arithmetic number, because the mean of its divisors is an integer number (5116527936).

Almost surely, 2^20400514921 is an apocalyptic number.

It is an amenable number.

20400514921 is a deficient number, since it is larger than the sum of its proper divisors (65596823).

20400514921 is an equidigital number, since it uses as much as digits as its factorization.

20400514921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 65596822.

The product of its (nonzero) digits is 2880, while the sum is 28.

The spelling of 20400514921 in words is "twenty billion, four hundred million, five hundred fourteen thousand, nine hundred twenty-one".