231321405 has 24 divisors (see below), whose sum is σ = 430542432. Its totient is φ = 105746592.

The previous prime is 231321383. The next prime is 231321407. The reversal of 231321405 is 504123132.

It is not a de Polignac number, because 231321405 - 2¹² = 231317309 is a prime.

It is a super-2 number, since 2×231321405² = 107019184822348050, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (231321407) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 156627 + ... + 158096.

It is an arithmetic number, because the mean of its divisors is an integer number (17939268).

Almost surely, 2^231321405 is an apocalyptic number.

It is an amenable number.

231321405 is a deficient number, since it is larger than the sum of its proper divisors (199221027).

231321405 is a wasteful number, since it uses less digits than its factorization.

231321405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 314745 (or 314738 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 21.

The square root of 231321405 is about 15209.2539264752. The cubic root of 231321405 is about 613.8636827037.

Adding to 231321405 its reverse (504123132), we get a palindrome (735444537).

The spelling of 231321405 in words is "two hundred thirty-one million, three hundred twenty-one thousand, four hundred five".