61881861 has 4 divisors (see below), whose sum is σ = 82509152. Its totient is φ = 41254572.

The previous prime is 61881821. The next prime is 61881863. The reversal of 61881861 is 16818816.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 61881861 - 2¹⁴ = 61865477 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61881863) 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, 10313641 + ... + 10313646.

It is an arithmetic number, because the mean of its divisors is an integer number (20627288).

Almost surely, 2^61881861 is an apocalyptic number.

It is an amenable number.

61881861 is a deficient number, since it is larger than the sum of its proper divisors (20627291).

61881861 is a wasteful number, since it uses less digits than its factorization.

61881861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20627290.

The product of its digits is 18432, while the sum is 39.

The square root of 61881861 is about 7866.5024629755. The cubic root of 61881861 is about 395.5376133021.

The spelling of 61881861 in words is "sixty-one million, eight hundred eighty-one thousand, eight hundred sixty-one".