1861380864 has 576 divisors, whose sum is σ = 6969876480. Its totient is φ = 477757440.

The previous prime is 1861380797. The next prime is 1861380883. The reversal of 1861380864 is 4680831681.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (576).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 25498332 + ... + 25498404.

It is an arithmetic number, because the mean of its divisors is an integer number (12100480).

Almost surely, 2^1861380864 is an apocalyptic number.

1861380864 is a gapful number since it is divisible by the number (14) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1861380864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3484938240).

1861380864 is an abundant number, since it is smaller than the sum of its proper divisors (5108495616).

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

1861380864 is a wasteful number, since it uses less digits than its factorization.

1861380864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 153 (or 133 counting only the distinct ones).

The product of its (nonzero) digits is 221184, while the sum is 45.

The square root of 1861380864 is about 43143.7233441899. The cubic root of 1861380864 is about 1230.1132079026.

The spelling of 1861380864 in words is "one billion, eight hundred sixty-one million, three hundred eighty thousand, eight hundred sixty-four".