661771551203 has 8 divisors (see below), whose sum is σ = 756893477472. Its totient is φ = 566795408256.

The previous prime is 661771551193. The next prime is 661771551209. The reversal of 661771551203 is 302155177166.

It is a happy number.

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

It is not a de Polignac number, because 661771551203 - 2¹⁸ = 661771289059 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (661771551209) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 36436100 + ... + 36454257.

It is an arithmetic number, because the mean of its divisors is an integer number (94611684684).

Almost surely, 2^661771551203 is an apocalyptic number.

661771551203 is a deficient number, since it is larger than the sum of its proper divisors (95121926269).

661771551203 is a wasteful number, since it uses less digits than its factorization.

661771551203 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72891661.

The product of its (nonzero) digits is 264600, while the sum is 44.

The spelling of 661771551203 in words is "six hundred sixty-one billion, seven hundred seventy-one million, five hundred fifty-one thousand, two hundred three".