781079904 has 144 divisors (see below), whose sum is σ = 2433294864. Its totient is φ = 235699200.

The previous prime is 781079899. The next prime is 781079927. The reversal of 781079904 is 409970187.

It is a tau number, because it is divible by the number of its divisors (144).

It is a super-2 number, since 2×781079904² = 1220171632865298432, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 781079904.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1181334 + ... + 1181994.

It is an arithmetic number, because the mean of its divisors is an integer number (16897881).

Almost surely, 2^781079904 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 781079904, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1216647432).

781079904 is an abundant number, since it is smaller than the sum of its proper divisors (1652214960).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

781079904 is a wasteful number, since it uses less digits than its factorization.

781079904 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1061 (or 1050 counting only the distinct ones).

The product of its (nonzero) digits is 127008, while the sum is 45.

The square root of 781079904 is about 27947.8067833596. The cubic root of 781079904 is about 920.9410283129.

The spelling of 781079904 in words is "seven hundred eighty-one million, seventy-nine thousand, nine hundred four".