891409780 has 48 divisors (see below), whose sum is σ = 1929533760. Its totient is φ = 345719808.

The previous prime is 891409777. The next prime is 891409787. The reversal of 891409780 is 87904198.

It is a happy number.

891409780 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×891409780² = 1589222791759296800, 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 891409780.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (891409787) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 115812 + ... + 123268.

It is an arithmetic number, because the mean of its divisors is an integer number (40198620).

Almost surely, 2^891409780 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 891409780, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (964766880).

891409780 is an abundant number, since it is smaller than the sum of its proper divisors (1038123980).

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

891409780 is a wasteful number, since it uses less digits than its factorization.

891409780 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7648 (or 7646 counting only the distinct ones).

The product of its (nonzero) digits is 145152, while the sum is 46.

The square root of 891409780 is about 29856.4863974313. The cubic root of 891409780 is about 962.4077941693.

The spelling of 891409780 in words is "eight hundred ninety-one million, four hundred nine thousand, seven hundred eighty".