781320947 has 4 divisors (see below), whose sum is σ = 852350136. Its totient is φ = 710291760.

The previous prime is 781320941. The next prime is 781320949. The reversal of 781320947 is 749023187.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 781320947 - 2⁸ = 781320691 is a prime.

It is a super-2 number, since 2×781320947² = 1220924844441953618, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (781320941) 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, 35514578 + ... + 35514599.

It is an arithmetic number, because the mean of its divisors is an integer number (213087534).

Almost surely, 2^781320947 is an apocalyptic number.

781320947 is a deficient number, since it is larger than the sum of its proper divisors (71029189).

781320947 is a wasteful number, since it uses less digits than its factorization.

781320947 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 71029188.

The product of its (nonzero) digits is 84672, while the sum is 41.

The square root of 781320947 is about 27952.1188284538. The cubic root of 781320947 is about 921.0357533877.

The spelling of 781320947 in words is "seven hundred eighty-one million, three hundred twenty thousand, nine hundred forty-seven".