781172961 has 4 divisors (see below), whose sum is σ = 1041563952. Its totient is φ = 520781972.

The previous prime is 781172957. The next prime is 781173007. The reversal of 781172961 is 169271187.

781172961 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 781172961 - 2² = 781172957 is a prime.

It is a super-2 number, since 2×781172961² = 1220462389995015042, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (781172941) 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, 130195491 + ... + 130195496.

It is an arithmetic number, because the mean of its divisors is an integer number (260390988).

Almost surely, 2^781172961 is an apocalyptic number.

It is an amenable number.

781172961 is a deficient number, since it is larger than the sum of its proper divisors (260390991).

781172961 is a wasteful number, since it uses less digits than its factorization.

781172961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 260390990.

The product of its digits is 42336, while the sum is 42.

The square root of 781172961 is about 27949.4715692444. The cubic root of 781172961 is about 920.9776001607.

The spelling of 781172961 in words is "seven hundred eighty-one million, one hundred seventy-two thousand, nine hundred sixty-one".