61559981 has 16 divisors (see below), whose sum is σ = 74386560. Its totient is φ = 49766400.

The previous prime is 61559959. The next prime is 61559999. The reversal of 61559981 is 18995516.

It is a cyclic number.

It is not a de Polignac number, because 61559981 - 2⁶ = 61559917 is a prime.

It is a super-2 number, since 2×61559981² = 7579262521440722, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61559581) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 33281 + ... + 35081.

It is an arithmetic number, because the mean of its divisors is an integer number (4649160).

Almost surely, 2^61559981 is an apocalyptic number.

It is an amenable number.

61559981 is a deficient number, since it is larger than the sum of its proper divisors (12826579).

61559981 is a wasteful number, since it uses less digits than its factorization.

61559981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2084.

The product of its digits is 97200, while the sum is 44.

The square root of 61559981 is about 7846.0168875679. The cubic root of 61559981 is about 394.8506212920.

The spelling of 61559981 in words is "sixty-one million, five hundred fifty-nine thousand, nine hundred eighty-one".