997287521 has 4 divisors (see below), whose sum is σ = 1040647872. Its totient is φ = 953927172.

The previous prime is 997287493. The next prime is 997287539. The reversal of 997287521 is 125782799.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 997287521 - 2⁶ = 997287457 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 997287521.

It is not an unprimeable number, because it can be changed into a prime (993287521) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21680141 + ... + 21680186.

It is an arithmetic number, because the mean of its divisors is an integer number (260161968).

Almost surely, 2^997287521 is an apocalyptic number.

It is an amenable number.

997287521 is a deficient number, since it is larger than the sum of its proper divisors (43360351).

997287521 is a wasteful number, since it uses less digits than its factorization.

997287521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43360350.

The product of its digits is 635040, while the sum is 50.

The square root of 997287521 is about 31579.8594202064. The cubic root of 997287521 is about 999.0950215945.

The spelling of 997287521 in words is "nine hundred ninety-seven million, two hundred eighty-seven thousand, five hundred twenty-one".