1922561991 has 24 divisors (see below), whose sum is σ = 3238528800. Its totient is φ = 1098605088.

The previous prime is 1922561957. The next prime is 1922562007. The reversal of 1922561991 is 1991652291.

1922561991 is a `hidden beast` number, since 1 + 9 + 2 + 25 + 619 + 9 + 1 = 666.

It is not a de Polignac number, because 1922561991 - 2¹⁰ = 1922560967 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1922561491) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 308310 + ... + 314483.

It is an arithmetic number, because the mean of its divisors is an integer number (134938700).

Almost surely, 2^1922561991 is an apocalyptic number.

1922561991 is a deficient number, since it is larger than the sum of its proper divisors (1315966809).

1922561991 is an equidigital number, since it uses as much as digits as its factorization.

1922561991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 622820 (or 622803 counting only the distinct ones).

The product of its digits is 87480, while the sum is 45.

The square root of 1922561991 is about 43847.0294432816. The cubic root of 1922561991 is about 1243.4455831799.

The spelling of 1922561991 in words is "one billion, nine hundred twenty-two million, five hundred sixty-one thousand, nine hundred ninety-one".