1021396993 has 4 divisors (see below), whose sum is σ = 1038141268. Its totient is φ = 1004652720.

The previous prime is 1021396979. The next prime is 1021397051. The reversal of 1021396993 is 3996931201.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 3996931201 = 39563 ⋅101027.

It can be written as a sum of positive squares in 2 ways, for example, as 13778944 + 1007618049 = 3712^2 + 31743^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1021396993 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1021396933) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8372046 + ... + 8372167.

It is an arithmetic number, because the mean of its divisors is an integer number (259535317).

Almost surely, 2^1021396993 is an apocalyptic number.

It is an amenable number.

1021396993 is a deficient number, since it is larger than the sum of its proper divisors (16744275).

1021396993 is an equidigital number, since it uses as much as digits as its factorization.

1021396993 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16744274.

The product of its (nonzero) digits is 78732, while the sum is 43.

The square root of 1021396993 is about 31959.3021356850. The cubic root of 1021396993 is about 1007.0820570663.

The spelling of 1021396993 in words is "one billion, twenty-one million, three hundred ninety-six thousand, nine hundred ninety-three".