661772133 has 16 divisors (see below), whose sum is σ = 1069531200. Its totient is φ = 401073840.

The previous prime is 661772131. The next prime is 661772161. The reversal of 661772133 is 331277166.

661772133 is a `hidden beast` number, since 6 + 617 + 7 + 2 + 1 + 33 = 666.

It is not a de Polignac number, because 661772133 - 2¹ = 661772131 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661772131) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1113798 + ... + 1114391.

It is an arithmetic number, because the mean of its divisors is an integer number (66845700).

Almost surely, 2^661772133 is an apocalyptic number.

It is an amenable number.

661772133 is a deficient number, since it is larger than the sum of its proper divisors (407759067).

661772133 is a wasteful number, since it uses less digits than its factorization.

661772133 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2228209 (or 2228203 counting only the distinct ones).

The product of its digits is 31752, while the sum is 36.

The square root of 661772133 is about 25724.9321281903. The cubic root of 661772133 is about 871.4373268198.

The spelling of 661772133 in words is "six hundred sixty-one million, seven hundred seventy-two thousand, one hundred thirty-three".