978193781 has 4 divisors (see below), whose sum is σ = 987690912. Its totient is φ = 968696652.

The previous prime is 978193771. The next prime is 978193813. The reversal of 978193781 is 187391879.

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 978193781 - 2⁶ = 978193717 is a prime.

It is a super-2 number, since 2×978193781² = 1913726146374151922, 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 (978193771) 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, 4748411 + ... + 4748616.

It is an arithmetic number, because the mean of its divisors is an integer number (246922728).

Almost surely, 2^978193781 is an apocalyptic number.

It is an amenable number.

978193781 is a deficient number, since it is larger than the sum of its proper divisors (9497131).

978193781 is a wasteful number, since it uses less digits than its factorization.

978193781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9497130.

The product of its digits is 762048, while the sum is 53.

The square root of 978193781 is about 31276.0896053199. The cubic root of 978193781 is about 992.6777762327.

The spelling of 978193781 in words is "nine hundred seventy-eight million, one hundred ninety-three thousand, seven hundred eighty-one".