87721380 has 120 divisors (see below), whose sum is σ = 277660152. Its totient is φ = 23182848.

The previous prime is 87721367. The next prime is 87721391. The reversal of 87721380 is 8312778.

It can be written as a sum of positive squares in 4 ways, for example, as 3779136 + 83942244 = 1944^2 + 9162^2 .

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 280104 + ... + 280416.

Almost surely, 2^87721380 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 87721380, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (138830076).

87721380 is an abundant number, since it is smaller than the sum of its proper divisors (189938772).

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

87721380 is a wasteful number, since it uses less digits than its factorization.

87721380 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 507 (or 496 counting only the distinct ones).

The product of its (nonzero) digits is 18816, while the sum is 36.

The square root of 87721380 is about 9365.9692504300. The cubic root of 87721380 is about 444.3260935335.

The spelling of 87721380 in words is "eighty-seven million, seven hundred twenty-one thousand, three hundred eighty".