861249420 has 144 divisors (see below), whose sum is σ = 2669835168. Its totient is φ = 224686080.

The previous prime is 861249397. The next prime is 861249437. The reversal of 861249420 is 24942168.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1867990 + ... + 1868450.

It is an arithmetic number, because the mean of its divisors is an integer number (18540522).

Almost surely, 2^861249420 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 861249420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1334917584).

861249420 is an abundant number, since it is smaller than the sum of its proper divisors (1808585748).

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

861249420 is a wasteful number, since it uses less digits than its factorization.

861249420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 680 (or 675 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 36.

The square root of 861249420 is about 29347.0512999177. The cubic root of 861249420 is about 951.4288452544.

The spelling of 861249420 in words is "eight hundred sixty-one million, two hundred forty-nine thousand, four hundred twenty".