61518881 has 4 divisors (see below), whose sum is σ = 61543812. Its totient is φ = 61493952.

The previous prime is 61518871. The next prime is 61518883. The reversal of 61518881 is 18881516.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 6150400 + 55368481 = 2480^2 + 7441^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-61518881 is a prime.

It is a super-2 number, since 2×61518881² = 7569145438984322, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (61518883) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8300 + ... + 13853.

It is an arithmetic number, because the mean of its divisors is an integer number (15385953).

Almost surely, 2^61518881 is an apocalyptic number.

It is an amenable number.

61518881 is a deficient number, since it is larger than the sum of its proper divisors (24931).

61518881 is a wasteful number, since it uses less digits than its factorization.

61518881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24930.

The product of its digits is 15360, while the sum is 38.

The square root of 61518881 is about 7843.3972868904. The cubic root of 61518881 is about 394.7627288377.

The spelling of 61518881 in words is "sixty-one million, five hundred eighteen thousand, eight hundred eighty-one".