61621981775 has 12 divisors (see below), whose sum is σ = 76424333232. Its totient is φ = 49289149440.

The previous prime is 61621981747. The next prime is 61621981787. The reversal of 61621981775 is 57718912616.

It is not a de Polignac number, because 61621981775 - 2⁶ = 61621981711 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 59762 + ... + 356111.

It is an arithmetic number, because the mean of its divisors is an integer number (6368694436).

Almost surely, 2^61621981775 is an apocalyptic number.

61621981775 is a deficient number, since it is larger than the sum of its proper divisors (14802351457).

61621981775 is a wasteful number, since it uses less digits than its factorization.

61621981775 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 421810 (or 421805 counting only the distinct ones).

The product of its digits is 1270080, while the sum is 53.

The spelling of 61621981775 in words is "sixty-one billion, six hundred twenty-one million, nine hundred eighty-one thousand, seven hundred seventy-five".