661620772 has 12 divisors (see below), whose sum is σ = 1186076556. Its totient is φ = 322741760.

The previous prime is 661620769. The next prime is 661620797. The reversal of 661620772 is 277026166.

It can be written as a sum of positive squares in 2 ways, for example, as 388247616 + 273373156 = 19704^2 + 16534^2 .

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, 2016973 + ... + 2017300.

It is an arithmetic number, because the mean of its divisors is an integer number (98839713).

Almost surely, 2^661620772 is an apocalyptic number.

It is an amenable number.

661620772 is a deficient number, since it is larger than the sum of its proper divisors (524455784).

661620772 is a wasteful number, since it uses less digits than its factorization.

661620772 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4034318 (or 4034316 counting only the distinct ones).

The product of its (nonzero) digits is 42336, while the sum is 37.

The square root of 661620772 is about 25721.9900474283. The cubic root of 661620772 is about 871.3708831624.

The spelling of 661620772 in words is "six hundred sixty-one million, six hundred twenty thousand, seven hundred seventy-two".