87821657 has 32 divisors (see below), whose sum is σ = 115153920. Its totient is φ = 64975680.

The previous prime is 87821651. The next prime is 87821663. The reversal of 87821657 is 75612878.

It is an interprime number because it is at equal distance from previous prime (87821651) and next prime (87821663).

It is not a de Polignac number, because 87821657 - 2²² = 83627353 is a prime.

It is not an unprimeable number, because it can be changed into a prime (87821651) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 149318 + ... + 149904.

It is an arithmetic number, because the mean of its divisors is an integer number (3598560).

Almost surely, 2^87821657 is an apocalyptic number.

It is an amenable number.

87821657 is a deficient number, since it is larger than the sum of its proper divisors (27332263).

87821657 is a wasteful number, since it uses less digits than its factorization.

87821657 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 701.

The product of its digits is 188160, while the sum is 44.

The square root of 87821657 is about 9371.3209847918. The cubic root of 87821657 is about 444.4953366560.

The spelling of 87821657 in words is "eighty-seven million, eight hundred twenty-one thousand, six hundred fifty-seven".