997637551 has 2 divisors, whose sum is σ = 997637552. Its totient is φ = 997637550.

The previous prime is 997637527. The next prime is 997637561. The reversal of 997637551 is 155736799.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 997637551 - 2⁷ = 997637423 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (997637561) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 498818775 + 498818776.

It is an arithmetic number, because the mean of its divisors is an integer number (498818776).

Almost surely, 2^997637551 is an apocalyptic number.

997637551 is a deficient number, since it is larger than the sum of its proper divisors (1).

997637551 is an equidigital number, since it uses as much as digits as its factorization.

997637551 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1786050, while the sum is 52.

The square root of 997637551 is about 31585.4009156129. The cubic root of 997637551 is about 999.2118960553.

The spelling of 997637551 in words is "nine hundred ninety-seven million, six hundred thirty-seven thousand, five hundred fifty-one".