661157876 has 18 divisors (see below), whose sum is σ = 1174584978. Its totient is φ = 325636080.

The previous prime is 661157867. The next prime is 661157909. The reversal of 661157876 is 678751166.

It can be written as a sum of positive squares in only one way, i.e., 518928400 + 142229476 = 22780^2 + 11926^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 661157876.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 455 + ... + 36366.

It is an arithmetic number, because the mean of its divisors is an integer number (65254721).

Almost surely, 2^661157876 is an apocalyptic number.

It is an amenable number.

661157876 is a deficient number, since it is larger than the sum of its proper divisors (513427102).

661157876 is a wasteful number, since it uses less digits than its factorization.

661157876 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36959 (or 36890 counting only the distinct ones).

The product of its digits is 423360, while the sum is 47.

The square root of 661157876 is about 25712.9904134078. The cubic root of 661157876 is about 871.1676206000.

The spelling of 661157876 in words is "six hundred sixty-one million, one hundred fifty-seven thousand, eight hundred seventy-six".