61918591633 has 4 divisors (see below), whose sum is σ = 61972294948. Its totient is φ = 61864888320.

The previous prime is 61918591607. The next prime is 61918591661. The reversal of 61918591633 is 33619581916.

61918591633 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 19561658769 + 42356932864 = 139863^2 + 205808^2 .

It is a cyclic number.

It is not a de Polignac number, because 61918591633 - 2⁵ = 61918591601 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (61918591333) 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, 26849928 + ... + 26852233.

It is an arithmetic number, because the mean of its divisors is an integer number (15493073737).

Almost surely, 2^61918591633 is an apocalyptic number.

It is an amenable number.

61918591633 is a deficient number, since it is larger than the sum of its proper divisors (53703315).

61918591633 is a wasteful number, since it uses less digits than its factorization.

61918591633 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53703314.

The product of its digits is 1049760, while the sum is 52.

The spelling of 61918591633 in words is "sixty-one billion, nine hundred eighteen million, five hundred ninety-one thousand, six hundred thirty-three".