61545561 has 48 divisors (see below), whose sum is σ = 105259392. Its totient is φ = 31299840.

The previous prime is 61545557. The next prime is 61545581. The reversal of 61545561 is 16554516.

It is not a de Polignac number, because 61545561 - 2² = 61545557 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is not an unprimeable number, because it can be changed into a prime (61545521) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 134445 + ... + 134901.

It is an arithmetic number, because the mean of its divisors is an integer number (2192904).

Almost surely, 2^61545561 is an apocalyptic number.

It is an amenable number.

61545561 is a deficient number, since it is larger than the sum of its proper divisors (43713831).

61545561 is a wasteful number, since it uses less digits than its factorization.

61545561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 542 (or 531 counting only the distinct ones).

The product of its digits is 18000, while the sum is 33.

The square root of 61545561 is about 7845.0978961387. The cubic root of 61545561 is about 394.8197885416.

It can be divided in two parts, 615455 and 61, that added together give a palindrome (615516).

The spelling of 61545561 in words is "sixty-one million, five hundred forty-five thousand, five hundred sixty-one".