661917070690 has 8 divisors (see below), whose sum is σ = 1191450727260. Its totient is φ = 264766828272.

The previous prime is 661917070687. The next prime is 661917070723. The reversal of 661917070690 is 96070719166.

661917070690 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 661848958681 + 68112009 = 813541^2 + 8253^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-4 number, since 4×661917070690⁴ (a number of 48 digits) contains 4444 as substring. Note that it is a super-d number also for d = 2.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 33095853525 + ... + 33095853544.

Almost surely, 2^661917070690 is an apocalyptic number.

661917070690 is a deficient number, since it is larger than the sum of its proper divisors (529533656570).

661917070690 is a wasteful number, since it uses less digits than its factorization.

661917070690 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66191707076.

The product of its (nonzero) digits is 857304, while the sum is 52.

The spelling of 661917070690 in words is "six hundred sixty-one billion, nine hundred seventeen million, seventy thousand, six hundred ninety".