61999648981 has 4 divisors (see below), whose sum is σ = 62010383200. Its totient is φ = 61988914764.

The previous prime is 61999648979. The next prime is 61999649021. The reversal of 61999648981 is 18984699916.

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 61999648981 - 2¹ = 61999648979 is a prime.

It is a super-2 number, since 2×61999648981² (a number of 22 digits) contains 22 as substring.

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 61999648981.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61999648901) 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, 5358441 + ... + 5369998.

It is an arithmetic number, because the mean of its divisors is an integer number (15502595800).

Almost surely, 2^61999648981 is an apocalyptic number.

It is an amenable number.

61999648981 is a deficient number, since it is larger than the sum of its proper divisors (10734219).

61999648981 is a wasteful number, since it uses less digits than its factorization.

61999648981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10734218.

The product of its digits is 60466176, while the sum is 70.

The spelling of 61999648981 in words is "sixty-one billion, nine hundred ninety-nine million, six hundred forty-eight thousand, nine hundred eighty-one".