1990497637 has 2 divisors, whose sum is σ = 1990497638. Its totient is φ = 1990497636.

The previous prime is 1990497571. The next prime is 1990497659. The reversal of 1990497637 is 7367940991.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1757202561 + 233295076 = 41919^2 + 15274^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1990497637 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1990497137) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 995248818 + 995248819.

It is an arithmetic number, because the mean of its divisors is an integer number (995248819).

Almost surely, 2^1990497637 is an apocalyptic number.

It is an amenable number.

1990497637 is a deficient number, since it is larger than the sum of its proper divisors (1).

1990497637 is an equidigital number, since it uses as much as digits as its factorization.

1990497637 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2571912, while the sum is 55.

The square root of 1990497637 is about 44614.9934102875. The cubic root of 1990497637 is about 1257.9225102089.

The spelling of 1990497637 in words is "one billion, nine hundred ninety million, four hundred ninety-seven thousand, six hundred thirty-seven".