1012020021991 has 32 divisors (see below), whose sum is σ = 1151816472576. Its totient is φ = 880830720000.

The previous prime is 1012020021967. The next prime is 1012020022033. The reversal of 1012020021991 is 1991200202101.

It is not a de Polignac number, because 1012020021991 - 2¹⁵ = 1012019989223 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1012020021931) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 138952836 + ... + 138960118.

It is an arithmetic number, because the mean of its divisors is an integer number (35994264768).

Almost surely, 2^{1012020021991} is an apocalyptic number.

1012020021991 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1012020021991 is a deficient number, since it is larger than the sum of its proper divisors (139796450585).

1012020021991 is a wasteful number, since it uses less digits than its factorization.

1012020021991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11623.

The product of its (nonzero) digits is 648, while the sum is 28.

The spelling of 1012020021991 in words is "one trillion, twelve billion, twenty million, twenty-one thousand, nine hundred ninety-one".