20400213021 has 4 divisors (see below), whose sum is σ = 27200284032. Its totient is φ = 13600142012.

The previous prime is 20400212971. The next prime is 20400213157. The reversal of 20400213021 is 12031200402.

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.

It is a cyclic number.

It is not a de Polignac number, because 20400213021 - 2⁶ = 20400212957 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20400213221) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3400035501 + ... + 3400035506.

It is an arithmetic number, because the mean of its divisors is an integer number (6800071008).

Almost surely, 2^20400213021 is an apocalyptic number.

It is an amenable number.

20400213021 is a deficient number, since it is larger than the sum of its proper divisors (6800071011).

20400213021 is an equidigital number, since it uses as much as digits as its factorization.

20400213021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6800071010.

The product of its (nonzero) digits is 96, while the sum is 15.

Adding to 20400213021 its reverse (12031200402), we get a palindrome (32431413423).

The spelling of 20400213021 in words is "twenty billion, four hundred million, two hundred thirteen thousand, twenty-one".