981778806451 has 4 divisors (see below), whose sum is σ = 982246545000. Its totient is φ = 981311067904.

The previous prime is 981778806431. The next prime is 981778806527. The reversal of 981778806451 is 154608877189.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 154608877189 = 13 ⋅11892990553.

It is a cyclic number.

It is not a de Polignac number, because 981778806451 - 2²⁹ = 981241935539 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (981778806431) 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, 233866126 + ... + 233870323.

It is an arithmetic number, because the mean of its divisors is an integer number (245561636250).

Almost surely, 2^981778806451 is an apocalyptic number.

981778806451 is a deficient number, since it is larger than the sum of its proper divisors (467738549).

981778806451 is a wasteful number, since it uses less digits than its factorization.

981778806451 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 467738548.

The product of its (nonzero) digits is 27095040, while the sum is 64.

The spelling of 981778806451 in words is "nine hundred eighty-one billion, seven hundred seventy-eight million, eight hundred six thousand, four hundred fifty-one".