1656990191 has 2 divisors, whose sum is σ = 1656990192. Its totient is φ = 1656990190.

The previous prime is 1656990157. The next prime is 1656990229. The reversal of 1656990191 is 1910996561.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1656990191 - 2¹⁴ = 1656973807 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1656990121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 828495095 + 828495096.

It is an arithmetic number, because the mean of its divisors is an integer number (828495096).

Almost surely, 2^1656990191 is an apocalyptic number.

1656990191 is a deficient number, since it is larger than the sum of its proper divisors (1).

1656990191 is an equidigital number, since it uses as much as digits as its factorization.

1656990191 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 131220, while the sum is 47.

The square root of 1656990191 is about 40706.1443887775. The cubic root of 1656990191 is about 1183.3321003933.

The spelling of 1656990191 in words is "one billion, six hundred fifty-six million, nine hundred ninety thousand, one hundred ninety-one".