997643957 has 2 divisors, whose sum is σ = 997643958. Its totient is φ = 997643956.

The previous prime is 997643947. The next prime is 997644029. The reversal of 997643957 is 759346799.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 800550436 + 197093521 = 28294^2 + 14039^2 .

It is a cyclic number.

It is not a de Polignac number, because 997643957 - 2⁶ = 997643893 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 997643896 and 997643905.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (997643917) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 498821978 + 498821979.

It is an arithmetic number, because the mean of its divisors is an integer number (498821979).

Almost surely, 2^997643957 is an apocalyptic number.

It is an amenable number.

997643957 is a deficient number, since it is larger than the sum of its proper divisors (1).

997643957 is an equidigital number, since it uses as much as digits as its factorization.

997643957 is an evil number, because the sum of its binary digits is even.

The product of its digits is 12859560, while the sum is 59.

The square root of 997643957 is about 31585.5023230595. The cubic root of 997643957 is about 999.2140347538.

The spelling of 997643957 in words is "nine hundred ninety-seven million, six hundred forty-three thousand, nine hundred fifty-seven".