61566660 has 36 divisors (see below), whose sum is σ = 186752748. Its totient is φ = 16417728.

The previous prime is 61566649. The next prime is 61566683. The reversal of 61566660 is 6666516.

It can be written as a sum of positive squares in 2 ways, for example, as 20196036 + 41370624 = 4494^2 + 6432^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 170839 + ... + 171198.

Almost surely, 2^61566660 is an apocalyptic number.

61566660 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

61566660 is an abundant number, since it is smaller than the sum of its proper divisors (125186088).

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

61566660 is a wasteful number, since it uses less digits than its factorization.

61566660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 342052 (or 342047 counting only the distinct ones).

The product of its (nonzero) digits is 38880, while the sum is 36.

The square root of 61566660 is about 7846.4425060023. The cubic root of 61566660 is about 394.8649006549.

It can be divided in two parts, 61566 and 660, that added together give a palindrome (62226).

The spelling of 61566660 in words is "sixty-one million, five hundred sixty-six thousand, six hundred sixty".