61891979 has 4 divisors (see below), whose sum is σ = 62492976. Its totient is φ = 61290984.

The previous prime is 61891957. The next prime is 61892029. The reversal of 61891979 is 97919816.

61891979 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 is a cyclic number.

It is not a de Polignac number, because 61891979 - 2²⁰ = 60843403 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (61891909) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 300344 + ... + 300549.

It is an arithmetic number, because the mean of its divisors is an integer number (15623244).

Almost surely, 2^61891979 is an apocalyptic number.

61891979 is a deficient number, since it is larger than the sum of its proper divisors (600997).

61891979 is a wasteful number, since it uses less digits than its factorization.

61891979 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 600996.

The product of its digits is 244944, while the sum is 50.

The square root of 61891979 is about 7867.1455433340. The cubic root of 61891979 is about 395.5591695999.

The spelling of 61891979 in words is "sixty-one million, eight hundred ninety-one thousand, nine hundred seventy-nine".