61566516 has 72 divisors (see below), whose sum is σ = 171478944. Its totient is φ = 18469440.

The previous prime is 61566511. The next prime is 61566523.

61566516 is nontrivially palindromic in base 10.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61566511) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 41646 + ... + 43098.

It is an arithmetic number, because the mean of its divisors is an integer number (2381652).

Almost surely, 2^61566516 is an apocalyptic number.

61566516 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 61566516, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (85739472).

61566516 is an abundant number, since it is smaller than the sum of its proper divisors (109912428).

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

61566516 is a wasteful number, since it uses less digits than its factorization.

61566516 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1581 (or 1576 counting only the distinct ones).

The product of its digits is 32400, while the sum is 36.

The square root of 61566516 is about 7846.4333298640. The cubic root of 61566516 is about 394.8645928011.

The spelling of 61566516 in words is "sixty-one million, five hundred sixty-six thousand, five hundred sixteen".