661455771 has 32 divisors (see below), whose sum is σ = 965260800. Its totient is φ = 401204736.

The previous prime is 661455763. The next prime is 661455841. The reversal of 661455771 is 177554166.

It is not a de Polignac number, because 661455771 - 2³ = 661455763 is a prime.

It is not an unprimeable number, because it can be changed into a prime (661455761) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 314080 + ... + 316178.

It is an arithmetic number, because the mean of its divisors is an integer number (30164400).

Almost surely, 2^661455771 is an apocalyptic number.

661455771 is a deficient number, since it is larger than the sum of its proper divisors (303805029).

661455771 is a wasteful number, since it uses less digits than its factorization.

661455771 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2323.

The product of its digits is 176400, while the sum is 42.

The square root of 661455771 is about 25718.7824556296. The cubic root of 661455771 is about 871.2984403437.

The spelling of 661455771 in words is "six hundred sixty-one million, four hundred fifty-five thousand, seven hundred seventy-one".