61555566 has 16 divisors (see below), whose sum is σ = 123793488. Its totient is φ = 20404800.

The previous prime is 61555547. The next prime is 61555577. The reversal of 61555566 is 66555516.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 27255 + ... + 29426.

It is an arithmetic number, because the mean of its divisors is an integer number (7737093).

Almost surely, 2^61555566 is an apocalyptic number.

61555566 is an abundant number, since it is smaller than the sum of its proper divisors (62237922).

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

61555566 is a wasteful number, since it uses less digits than its factorization.

61555566 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56867.

The product of its digits is 135000, while the sum is 39.

The square root of 61555566 is about 7845.7355295727. The cubic root of 61555566 is about 394.8411816791.

The spelling of 61555566 in words is "sixty-one million, five hundred fifty-five thousand, five hundred sixty-six".