1231200021 has 16 divisors (see below), whose sum is σ = 1648987200. Its totient is φ = 817116288.

The previous prime is 1231200007. The next prime is 1231200031. The reversal of 1231200021 is 1200021321.

It is a de Polignac number, because none of the positive numbers 2^k-1231200021 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1231200001) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 977290 + ... + 978548.

It is an arithmetic number, because the mean of its divisors is an integer number (103061700).

Almost surely, 2^1231200021 is an apocalyptic number.

It is an amenable number.

1231200021 is a deficient number, since it is larger than the sum of its proper divisors (417787179).

1231200021 is a wasteful number, since it uses less digits than its factorization.

1231200021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2468.

The product of its (nonzero) digits is 24, while the sum is 12.

The square root of 1231200021 is about 35088.4599405560. The cubic root of 1231200021 is about 1071.7895987185.

Adding to 1231200021 its reverse (1200021321), we get a palindrome (2431221342).

The spelling of 1231200021 in words is "one billion, two hundred thirty-one million, two hundred thousand, twenty-one".