64199512981 has 4 divisors (see below), whose sum is σ = 64227295264. Its totient is φ = 64171730700.

The previous prime is 64199512969. The next prime is 64199512999. The reversal of 64199512981 is 18921599146.

It is a happy number.

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 64199512981 - 2²¹ = 64197415829 is a prime.

It is a super-2 number, since 2×64199512981² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64199512921) 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, 13887675 + ... + 13892296.

It is an arithmetic number, because the mean of its divisors is an integer number (16056823816).

Almost surely, 2^64199512981 is an apocalyptic number.

It is an amenable number.

64199512981 is a deficient number, since it is larger than the sum of its proper divisors (27782283).

64199512981 is a wasteful number, since it uses less digits than its factorization.

64199512981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27782282.

The product of its digits is 1399680, while the sum is 55.

The spelling of 64199512981 in words is "sixty-four billion, one hundred ninety-nine million, five hundred twelve thousand, nine hundred eighty-one".