231320145221 has 4 divisors (see below), whose sum is σ = 252349249344. Its totient is φ = 210291041100.

The previous prime is 231320145179. The next prime is 231320145241. The reversal of 231320145221 is 122541023132.

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 231320145221 - 2¹⁸ = 231319883077 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 (231320145241) 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, 10514552045 + ... + 10514552066.

It is an arithmetic number, because the mean of its divisors is an integer number (63087312336).

Almost surely, 2^231320145221 is an apocalyptic number.

It is an amenable number.

231320145221 is a deficient number, since it is larger than the sum of its proper divisors (21029104123).

231320145221 is a wasteful number, since it uses less digits than its factorization.

231320145221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21029104122.

The product of its (nonzero) digits is 2880, while the sum is 26.

Adding to 231320145221 its reverse (122541023132), we get a palindrome (353861168353).

The spelling of 231320145221 in words is "two hundred thirty-one billion, three hundred twenty million, one hundred forty-five thousand, two hundred twenty-one".