87388021 has 6 divisors (see below), whose sum is σ = 101655510. Its totient is φ = 74903976.

The previous prime is 87388019. The next prime is 87388057. The reversal of 87388021 is 12088378.

It can be written as a sum of positive squares in only one way, i.e., 86285521 + 1102500 = 9289^2 + 1050^2 .

It is not a de Polignac number, because 87388021 - 2¹ = 87388019 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (87388001) by changing a digit.

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 5 ways as a sum of consecutive naturals, for example, 891666 + ... + 891763.

It is an arithmetic number, because the mean of its divisors is an integer number (16942585).

Almost surely, 2^87388021 is an apocalyptic number.

It is an amenable number.

87388021 is a deficient number, since it is larger than the sum of its proper divisors (14267489).

87388021 is a wasteful number, since it uses less digits than its factorization.

87388021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1783443 (or 1783436 counting only the distinct ones).

The product of its (nonzero) digits is 21504, while the sum is 37.

The square root of 87388021 is about 9348.1560213766. The cubic root of 87388021 is about 443.7625360209.

The spelling of 87388021 in words is "eighty-seven million, three hundred eighty-eight thousand, twenty-one".