231220737 has 20 divisors (see below), whose sum is σ = 376805616. Its totient is φ = 140133240.

The previous prime is 231220727. The next prime is 231220739. The reversal of 231220737 is 737022132.

It is a happy number.

It is not a de Polignac number, because 231220737 - 2⁴ = 231220721 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a self number, because there is not a number n which added to its sum of digits gives 231220737.

It is not an unprimeable number, because it can be changed into a prime (231220739) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 128863 + ... + 130644.

Almost surely, 2^231220737 is an apocalyptic number.

231220737 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

It is an amenable number.

231220737 is a deficient number, since it is larger than the sum of its proper divisors (145584879).

231220737 is a wasteful number, since it uses less digits than its factorization.

231220737 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 259530 (or 259521 counting only the distinct ones).

The product of its (nonzero) digits is 3528, while the sum is 27.

The square root of 231220737 is about 15205.9441337919. The cubic root of 231220737 is about 613.7746213453.

Adding to 231220737 its reverse (737022132), we get a palindrome (968242869).

The spelling of 231220737 in words is "two hundred thirty-one million, two hundred twenty thousand, seven hundred thirty-seven".