972117661 has 2 divisors, whose sum is σ = 972117662. Its totient is φ = 972117660.

The previous prime is 972117659. The next prime is 972117683. The reversal of 972117661 is 166711279.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 956664900 + 15452761 = 30930^2 + 3931^2 .

It is a cyclic number.

It is not a de Polignac number, because 972117661 - 2¹ = 972117659 is a prime.

It is a super-2 number, since 2×972117661² = 1890025493656221842, which contains 22 as substring.

Together with 972117659, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (972117631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 486058830 + 486058831.

It is an arithmetic number, because the mean of its divisors is an integer number (486058831).

Almost surely, 2^972117661 is an apocalyptic number.

It is an amenable number.

972117661 is a deficient number, since it is larger than the sum of its proper divisors (1).

972117661 is an equidigital number, since it uses as much as digits as its factorization.

972117661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 31752, while the sum is 40.

The square root of 972117661 is about 31178.8014683054. The cubic root of 972117661 is about 990.6181430209.

The spelling of 972117661 in words is "nine hundred seventy-two million, one hundred seventeen thousand, six hundred sixty-one".