61597681 has 4 divisors (see below), whose sum is σ = 65221092. Its totient is φ = 57974272.

The previous prime is 61597663. The next prime is 61597693. The reversal of 61597681 is 18679516.

It is a happy number.

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 33454656 + 28143025 = 5784^2 + 5305^2 .

It is a cyclic number.

It is not a de Polignac number, because 61597681 - 2⁷ = 61597553 is a prime.

It is a super-2 number, since 2×61597681² = 7588548609155522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (61597631) 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, 1811680 + ... + 1811713.

It is an arithmetic number, because the mean of its divisors is an integer number (16305273).

Almost surely, 2^61597681 is an apocalyptic number.

It is an amenable number.

61597681 is a deficient number, since it is larger than the sum of its proper divisors (3623411).

61597681 is a wasteful number, since it uses less digits than its factorization.

61597681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3623410.

The product of its digits is 90720, while the sum is 43.

The square root of 61597681 is about 7848.4190127694. The cubic root of 61597681 is about 394.9312084443.

The spelling of 61597681 in words is "sixty-one million, five hundred ninety-seven thousand, six hundred eighty-one".