781423749 has 12 divisors (see below), whose sum is σ = 1132922700. Its totient is φ = 519010944.

The previous prime is 781423729. The next prime is 781423771. The reversal of 781423749 is 947324187.

It can be written as a sum of positive squares in 2 ways, for example, as 20657025 + 760766724 = 4545^2 + 27582^2 .

It is not a de Polignac number, because 781423749 - 2⁸ = 781423493 is a prime.

It is a super-2 number, since 2×781423749² = 1221246151002430002, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (781423729) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 158964 + ... + 163805.

It is an arithmetic number, because the mean of its divisors is an integer number (94410225).

Almost surely, 2^781423749 is an apocalyptic number.

It is an amenable number.

781423749 is a deficient number, since it is larger than the sum of its proper divisors (351498951).

781423749 is a wasteful number, since it uses less digits than its factorization.

781423749 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 323044 (or 323041 counting only the distinct ones).

The product of its digits is 338688, while the sum is 45.

The square root of 781423749 is about 27953.9576625565. The cubic root of 781423749 is about 921.0761465900.

The spelling of 781423749 in words is "seven hundred eighty-one million, four hundred twenty-three thousand, seven hundred forty-nine".