1021021993 has 4 divisors (see below), whose sum is σ = 1048617220. Its totient is φ = 993426768.

The previous prime is 1021021979. The next prime is 1021021997. The reversal of 1021021993 is 3991201201.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 789160464 + 231861529 = 28092^2 + 15227^2 .

It is a cyclic number.

It is not a de Polignac number, because 1021021993 - 2²⁵ = 987467561 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1021021997) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13797558 + ... + 13797631.

It is an arithmetic number, because the mean of its divisors is an integer number (262154305).

Almost surely, 2^1021021993 is an apocalyptic number.

It is an amenable number.

1021021993 is a deficient number, since it is larger than the sum of its proper divisors (27595227).

1021021993 is an equidigital number, since it uses as much as digits as its factorization.

1021021993 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27595226.

The product of its (nonzero) digits is 972, while the sum is 28.

The square root of 1021021993 is about 31953.4347606012. The cubic root of 1021021993 is about 1006.9587938619.

The spelling of 1021021993 in words is "one billion, twenty-one million, twenty-one thousand, nine hundred ninety-three".