7861221888 has 160 divisors (see below), whose sum is σ = 23535743616. Its totient is φ = 2313535488.

The previous prime is 7861221877. The next prime is 7861221913. The reversal of 7861221888 is 8881221687.

It is a self number, because there is not a number n which added to its sum of digits gives 7861221888.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 450706 + ... + 467822.

Almost surely, 2^7861221888 is an apocalyptic number.

7861221888 is a gapful number since it is divisible by the number (78) 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 7861221888, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (11767871808).

7861221888 is an abundant number, since it is smaller than the sum of its proper divisors (15674521728).

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

7861221888 is a wasteful number, since it uses less digits than its factorization.

7861221888 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17174 (or 17158 counting only the distinct ones).

The product of its digits is 688128, while the sum is 51.

The square root of 7861221888 is about 88663.5318944604. The cubic root of 7861221888 is about 1988.3676325132.

The spelling of 7861221888 in words is "seven billion, eight hundred sixty-one million, two hundred twenty-one thousand, eight hundred eighty-eight".