667297710361621 has 4 divisors (see below), whose sum is σ = 667417062488544. Its totient is φ = 667178358234700.

The previous prime is 667297710361609. The next prime is 667297710361627. The reversal of 667297710361621 is 126163017792766.

It is a happy number.

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 667297710361621 - 2⁵ = 667297710361589 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (667297710361627) 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, 59676055075 + ... + 59676066256.

It is an arithmetic number, because the mean of its divisors is an integer number (166854265622136).

Almost surely, 2^{667297710361621} is an apocalyptic number.

It is an amenable number.

667297710361621 is a deficient number, since it is larger than the sum of its proper divisors (119352126923).

667297710361621 is a wasteful number, since it uses less digits than its factorization.

667297710361621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 119352126922.

The product of its (nonzero) digits is 48009024, while the sum is 64.

The spelling of 667297710361621 in words is "six hundred sixty-seven trillion, two hundred ninety-seven billion, seven hundred ten million, three hundred sixty-one thousand, six hundred twenty-one".