781790897 has 4 divisors (see below), whose sum is σ = 781847040. Its totient is φ = 781734756.

The previous prime is 781790881. The next prime is 781790923. The reversal of 781790897 is 798097187.

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, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 798097187 = 877 ⋅910031.

It is a cyclic number.

It is not a de Polignac number, because 781790897 - 2⁴ = 781790881 is a prime.

It is a super-2 number, since 2×781790897² = 1222394013264129218, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (781790857) 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, 10304 + ... + 40862.

It is an arithmetic number, because the mean of its divisors is an integer number (195461760).

Almost surely, 2^781790897 is an apocalyptic number.

It is an amenable number.

781790897 is a deficient number, since it is larger than the sum of its proper divisors (56143).

781790897 is a wasteful number, since it uses less digits than its factorization.

781790897 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 56142.

The product of its (nonzero) digits is 1778112, while the sum is 56.

The square root of 781790897 is about 27960.5239042476. The cubic root of 781790897 is about 921.2203783279.

The spelling of 781790897 in words is "seven hundred eighty-one million, seven hundred ninety thousand, eight hundred ninety-seven".