997695661 has 16 divisors (see below), whose sum is σ = 1047101440. Its totient is φ = 949469040.

The previous prime is 997695653. The next prime is 997695667. The reversal of 997695661 is 166596799.

It is a 5-Lehmer number, since φ(997695661) divides (997695661-1)⁵.

It is a cyclic number.

It is not a de Polignac number, because 997695661 - 2³ = 997695653 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 997695596 and 997695605.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (997695667) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 751180 + ... + 752506.

It is an arithmetic number, because the mean of its divisors is an integer number (65443840).

It is a Poulet number, since it divides 2^997695660-1.

Almost surely, 2^997695661 is an apocalyptic number.

It is an amenable number.

997695661 is a deficient number, since it is larger than the sum of its proper divisors (49405779).

997695661 is a wasteful number, since it uses less digits than its factorization.

997695661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1744.

The product of its digits is 5511240, while the sum is 58.

The square root of 997695661 is about 31586.3207892277. The cubic root of 997695661 is about 999.2312962459.

The spelling of 997695661 in words is "nine hundred ninety-seven million, six hundred ninety-five thousand, six hundred sixty-one".