1312123021 has 16 divisors (see below), whose sum is σ = 1495698048. Its totient is φ = 1139406400.

The previous prime is 1312122983. The next prime is 1312123061. The reversal of 1312123021 is 1203212131.

It is not a de Polignac number, because 1312123021 - 2¹⁵ = 1312090253 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1312122986 and 1312123004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1312123061) 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, 204555 + ... + 210871.

It is an arithmetic number, because the mean of its divisors is an integer number (93481128).

Almost surely, 2^1312123021 is an apocalyptic number.

1312123021 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1312123021 is a deficient number, since it is larger than the sum of its proper divisors (183575027).

1312123021 is a wasteful number, since it uses less digits than its factorization.

1312123021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7172.

The product of its (nonzero) digits is 72, while the sum is 16.

The square root of 1312123021 is about 36223.2386873399. The cubic root of 1312123021 is about 1094.7749503791.

Adding to 1312123021 its reverse (1203212131), we get a palindrome (2515335152).

The spelling of 1312123021 in words is "one billion, three hundred twelve million, one hundred twenty-three thousand, twenty-one".