1231020021 has 32 divisors (see below), whose sum is σ = 2057158656. Its totient is φ = 636120000.

The previous prime is 1231019983. The next prime is 1231020023. The reversal of 1231020021 is 1200201321.

It is not a de Polignac number, because 1231020021 - 2²⁵ = 1197465589 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1231019979 and 1231020006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1231020023) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 30171 + ... + 58071.

It is an arithmetic number, because the mean of its divisors is an integer number (64286208).

Almost surely, 2^1231020021 is an apocalyptic number.

1231020021 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1231020021 is a deficient number, since it is larger than the sum of its proper divisors (826138635).

1231020021 is a wasteful number, since it uses less digits than its factorization.

1231020021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28113.

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

The square root of 1231020021 is about 35085.8949009427. The cubic root of 1231020021 is about 1071.7373647119.

Adding to 1231020021 its reverse (1200201321), we get a palindrome (2431221342).

The spelling of 1231020021 in words is "one billion, two hundred thirty-one million, twenty thousand, twenty-one".