1021031981 has 2 divisors, whose sum is σ = 1021031982. Its totient is φ = 1021031980.

The previous prime is 1021031933. The next prime is 1021031989. The reversal of 1021031981 is 1891301201.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 843902500 + 177129481 = 29050^2 + 13309^2 .

It is a cyclic number.

It is not a de Polignac number, because 1021031981 - 2¹⁰ = 1021030957 is a prime.

It is a super-2 number, since 2×1021031981² = 2085012612449568722, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 1021031981.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1021031989) 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 as a sum of consecutive naturals, namely, 510515990 + 510515991.

It is an arithmetic number, because the mean of its divisors is an integer number (510515991).

Almost surely, 2^1021031981 is an apocalyptic number.

It is an amenable number.

1021031981 is a deficient number, since it is larger than the sum of its proper divisors (1).

1021031981 is an equidigital number, since it uses as much as digits as its factorization.

1021031981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 432, while the sum is 26.

The square root of 1021031981 is about 31953.5910501465. The cubic root of 1021031981 is about 1006.9620773274.

The spelling of 1021031981 in words is "one billion, twenty-one million, thirty-one thousand, nine hundred eighty-one".