61681173949 has 4 divisors (see below), whose sum is σ = 62050522464. Its totient is φ = 61311825436.

The previous prime is 61681173943. The next prime is 61681173977. The reversal of 61681173949 is 94937118616.

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 a cyclic number.

It is not a de Polignac number, because 61681173949 - 2¹¹ = 61681171901 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 61681173949.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61681173943) 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, 184674007 + ... + 184674340.

It is an arithmetic number, because the mean of its divisors is an integer number (15512630616).

Almost surely, 2^61681173949 is an apocalyptic number.

It is an amenable number.

61681173949 is a deficient number, since it is larger than the sum of its proper divisors (369348515).

61681173949 is a wasteful number, since it uses less digits than its factorization.

61681173949 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 369348514.

The product of its digits is 1959552, while the sum is 55.

The spelling of 61681173949 in words is "sixty-one billion, six hundred eighty-one million, one hundred seventy-three thousand, nine hundred forty-nine".