351997661 has 2 divisors, whose sum is σ = 351997662. Its totient is φ = 351997660.

The previous prime is 351997651. The next prime is 351997721. The reversal of 351997661 is 166799153.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 255840025 + 96157636 = 15995^2 + 9806^2 .

It is a cyclic number.

It is not a de Polignac number, because 351997661 - 2²⁶ = 284888797 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (351997651) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 175998830 + 175998831.

It is an arithmetic number, because the mean of its divisors is an integer number (175998831).

Almost surely, 2^351997661 is an apocalyptic number.

It is an amenable number.

351997661 is a deficient number, since it is larger than the sum of its proper divisors (1).

351997661 is an equidigital number, since it uses as much as digits as its factorization.

351997661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 306180, while the sum is 47.

The square root of 351997661 is about 18761.6007046307. The cubic root of 351997661 is about 706.0681031442.

The spelling of 351997661 in words is "three hundred fifty-one million, nine hundred ninety-seven thousand, six hundred sixty-one".