87390021 has 8 divisors (see below), whose sum is σ = 120538080. Its totient is φ = 56250992.

The previous prime is 87390011. The next prime is 87390049. The reversal of 87390021 is 12009378.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 87390021 - 2⁵ = 87389989 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (87390001) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 502155 + ... + 502328.

It is an arithmetic number, because the mean of its divisors is an integer number (15067260).

Almost surely, 2^87390021 is an apocalyptic number.

It is an amenable number.

87390021 is a deficient number, since it is larger than the sum of its proper divisors (33148059).

87390021 is a wasteful number, since it uses less digits than its factorization.

87390021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1004515.

The product of its (nonzero) digits is 3024, while the sum is 30.

The square root of 87390021 is about 9348.2629937331. The cubic root of 87390021 is about 443.7659213755.

Adding to 87390021 its reverse (12009378), we get a palindrome (99399399).

The spelling of 87390021 in words is "eighty-seven million, three hundred ninety thousand, twenty-one".