2121664165431 has 4 divisors (see below), whose sum is σ = 2828885553912. Its totient is φ = 1414442776952.

The previous prime is 2121664165367. The next prime is 2121664165441. The reversal of 2121664165431 is 1345614661212.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 2121664165431 - 2⁶ = 2121664165367 is a prime.

It is a super-2 number, since 2×2121664165431² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2121664165441) 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, 353610694236 + ... + 353610694241.

It is an arithmetic number, because the mean of its divisors is an integer number (707221388478).

Almost surely, 2^{2121664165431} is an apocalyptic number.

2121664165431 is a deficient number, since it is larger than the sum of its proper divisors (707221388481).

2121664165431 is an equidigital number, since it uses as much as digits as its factorization.

2121664165431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 707221388480.

The product of its digits is 207360, while the sum is 42.

The spelling of 2121664165431 in words is "two trillion, one hundred twenty-one billion, six hundred sixty-four million, one hundred sixty-five thousand, four hundred thirty-one".