661111040 has 36 divisors (see below), whose sum is σ = 1583570604. Its totient is φ = 264443904.

The previous prime is 661111039. The next prime is 661111081. The reversal of 661111040 is 40111166.

It can be written as a sum of positive squares in 2 ways, for example, as 236421376 + 424689664 = 15376^2 + 20608^2 .

It is a Harshad number since it is a multiple of its sum of digits (20).

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, 256967 + ... + 259526.

Almost surely, 2^661111040 is an apocalyptic number.

It is an amenable number.

661111040 is an abundant number, since it is smaller than the sum of its proper divisors (922459564).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

661111040 is an equidigital number, since it uses as much as digits as its factorization.

661111040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 516514 (or 516500 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 20.

The square root of 661111040 is about 25712.0796514012. The cubic root of 661111040 is about 871.1470491290.

The spelling of 661111040 in words is "six hundred sixty-one million, one hundred eleven thousand, forty".