87991323420 has 288 divisors, whose sum is σ = 333306699264. Its totient is φ = 16877329920.

The previous prime is 87991323403. The next prime is 87991323437. The reversal of 87991323420 is 2432319978.

It is an interprime number because it is at equal distance from previous prime (87991323403) and next prime (87991323437).

It is a self number, because there is not a number n which added to its sum of digits gives 87991323420.

It is a congruent number.

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 95 ways as a sum of consecutive naturals, for example, 594067 + ... + 727253.

It is an arithmetic number, because the mean of its divisors is an integer number (1157314928).

Almost surely, 2^87991323420 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 87991323420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (166653349632).

87991323420 is an abundant number, since it is smaller than the sum of its proper divisors (245315375844).

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

87991323420 is a wasteful number, since it uses less digits than its factorization.

87991323420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 133241 (or 133228 counting only the distinct ones).

The product of its (nonzero) digits is 653184, while the sum is 48.

The spelling of 87991323420 in words is "eighty-seven billion, nine hundred ninety-one million, three hundred twenty-three thousand, four hundred twenty".