1231331021 has 8 divisors (see below), whose sum is σ = 1237171584. Its totient is φ = 1225499760.

The previous prime is 1231330999. The next prime is 1231331027. The reversal of 1231331021 is 1201331321.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1231331021 - 2³⁰ = 157589197 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 (1231331027) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 480275 + ... + 482831.

It is an arithmetic number, because the mean of its divisors is an integer number (154646448).

Almost surely, 2^1231331021 is an apocalyptic number.

It is an amenable number.

1231331021 is a deficient number, since it is larger than the sum of its proper divisors (5840563).

1231331021 is a wasteful number, since it uses less digits than its factorization.

1231331021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4651.

The product of its (nonzero) digits is 108, while the sum is 17.

The square root of 1231331021 is about 35090.3266015009. The cubic root of 1231331021 is about 1071.8276102670.

Adding to 1231331021 its reverse (1201331321), we get a palindrome (2432662342).

It can be divided in two parts, 12313 and 31021, that added together give a palindrome (43334).

The spelling of 1231331021 in words is "one billion, two hundred thirty-one million, three hundred thirty-one thousand, twenty-one".