21140431421 has 4 divisors (see below), whose sum is σ = 21345678432. Its totient is φ = 20935184412.

The previous prime is 21140431381. The next prime is 21140431427. The reversal of 21140431421 is 12413404112.

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 21140431421 - 2¹⁰ = 21140430397 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21140431427) 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, 102623351 + ... + 102623556.

It is an arithmetic number, because the mean of its divisors is an integer number (5336419608).

Almost surely, 2^21140431421 is an apocalyptic number.

It is an amenable number.

21140431421 is a deficient number, since it is larger than the sum of its proper divisors (205247011).

21140431421 is a wasteful number, since it uses less digits than its factorization.

21140431421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 205247010.

The product of its (nonzero) digits is 768, while the sum is 23.

Adding to 21140431421 its reverse (12413404112), we get a palindrome (33553835533).

The spelling of 21140431421 in words is "twenty-one billion, one hundred forty million, four hundred thirty-one thousand, four hundred twenty-one".