6456509981 has 4 divisors (see below), whose sum is σ = 6456799200. Its totient is φ = 6456220764.

The previous prime is 6456509977. The next prime is 6456509987. The reversal of 6456509981 is 1899056546.

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 6456509981 - 2² = 6456509977 is a prime.

It is a super-2 number, since 2×6456509981² = 83373042269505240722, which 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 (6456509987) 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, 108041 + ... + 156798.

It is an arithmetic number, because the mean of its divisors is an integer number (1614199800).

Almost surely, 2^6456509981 is an apocalyptic number.

It is an amenable number.

6456509981 is a deficient number, since it is larger than the sum of its proper divisors (289219).

6456509981 is a wasteful number, since it uses less digits than its factorization.

6456509981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 289218.

The product of its (nonzero) digits is 2332800, while the sum is 53.

The square root of 6456509981 is about 80352.4111710408. The cubic root of 6456509981 is about 1862.0840306186.

The spelling of 6456509981 in words is "six billion, four hundred fifty-six million, five hundred nine thousand, nine hundred eighty-one".