1021040399 has 2 divisors, whose sum is σ = 1021040400. Its totient is φ = 1021040398.

The previous prime is 1021040393. The next prime is 1021040431. The reversal of 1021040399 is 9930401201.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1021040399 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1021040393) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 510520199 + 510520200.

It is an arithmetic number, because the mean of its divisors is an integer number (510520200).

Almost surely, 2^1021040399 is an apocalyptic number.

1021040399 is a deficient number, since it is larger than the sum of its proper divisors (1).

1021040399 is an equidigital number, since it uses as much as digits as its factorization.

1021040399 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1944, while the sum is 29.

The square root of 1021040399 is about 31953.7227721591. The cubic root of 1021040399 is about 1006.9648446529.

The spelling of 1021040399 in words is "one billion, twenty-one million, forty thousand, three hundred ninety-nine".