31437621221 has 4 divisors (see below), whose sum is σ = 31438132992. Its totient is φ = 31437109452.

The previous prime is 31437621199. The next prime is 31437621239. The reversal of 31437621221 is 12212673413.

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 31437621221 - 2¹⁰ = 31437620197 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 (31437626221) 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, 148805 + ... + 291578.

It is an arithmetic number, because the mean of its divisors is an integer number (7859533248).

Almost surely, 2^31437621221 is an apocalyptic number.

It is an amenable number.

31437621221 is a deficient number, since it is larger than the sum of its proper divisors (511771).

31437621221 is an equidigital number, since it uses as much as digits as its factorization.

31437621221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 511770.

The product of its digits is 12096, while the sum is 32.

The spelling of 31437621221 in words is "thirty-one billion, four hundred thirty-seven million, six hundred twenty-one thousand, two hundred twenty-one".