1021955591 has 2 divisors, whose sum is σ = 1021955592. Its totient is φ = 1021955590.

The previous prime is 1021955581. The next prime is 1021955633. The reversal of 1021955591 is 1955591201.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1021955591 - 2²⁶ = 954846727 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1021955521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 510977795 + 510977796.

It is an arithmetic number, because the mean of its divisors is an integer number (510977796).

Almost surely, 2^1021955591 is an apocalyptic number.

1021955591 is a deficient number, since it is larger than the sum of its proper divisors (1).

1021955591 is an equidigital number, since it uses as much as digits as its factorization.

1021955591 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 20250, while the sum is 38.

The square root of 1021955591 is about 31968.0401494993. The cubic root of 1021955591 is about 1007.2656133475.

The spelling of 1021955591 in words is "one billion, twenty-one million, nine hundred fifty-five thousand, five hundred ninety-one".