997517491 has 2 divisors, whose sum is σ = 997517492. Its totient is φ = 997517490.

The previous prime is 997517471. The next prime is 997517497. The reversal of 997517491 is 194715799.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 997517491 - 2⁷ = 997517363 is a prime.

It is a super-2 number, since 2×997517491² = 1990082289701870162, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (997517497) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 498758745 + 498758746.

It is an arithmetic number, because the mean of its divisors is an integer number (498758746).

Almost surely, 2^997517491 is an apocalyptic number.

997517491 is a deficient number, since it is larger than the sum of its proper divisors (1).

997517491 is an equidigital number, since it uses as much as digits as its factorization.

997517491 is an evil number, because the sum of its binary digits is even.

The product of its digits is 714420, while the sum is 52.

The square root of 997517491 is about 31583.5002968322. The cubic root of 997517491 is about 999.1718112928.

The spelling of 997517491 in words is "nine hundred ninety-seven million, five hundred seventeen thousand, four hundred ninety-one".