661838410357 has 4 divisors (see below), whose sum is σ = 690613993440. Its totient is φ = 633062827276.

The previous prime is 661838410351. The next prime is 661838410369. The reversal of 661838410357 is 753014838166.

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 661838410357 - 2³⁹ = 112082596469 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 (661838410351) 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, 14387791507 + ... + 14387791552.

It is an arithmetic number, because the mean of its divisors is an integer number (172653498360).

Almost surely, 2^661838410357 is an apocalyptic number.

It is an amenable number.

661838410357 is a deficient number, since it is larger than the sum of its proper divisors (28775583083).

661838410357 is a wasteful number, since it uses less digits than its factorization.

661838410357 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28775583082.

The product of its (nonzero) digits is 2903040, while the sum is 52.

The spelling of 661838410357 in words is "six hundred sixty-one billion, eight hundred thirty-eight million, four hundred ten thousand, three hundred fifty-seven".