87405021 has 16 divisors (see below), whose sum is σ = 141261120. Its totient is φ = 52972560.

The previous prime is 87405013. The next prime is 87405053. The reversal of 87405021 is 12050478.

It is not a de Polignac number, because 87405021 - 2³ = 87405013 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (87405011) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 146850 + ... + 147443.

It is an arithmetic number, because the mean of its divisors is an integer number (8828820).

Almost surely, 2^87405021 is an apocalyptic number.

It is an amenable number.

87405021 is a deficient number, since it is larger than the sum of its proper divisors (53856099).

87405021 is a wasteful number, since it uses less digits than its factorization.

87405021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 294313 (or 294307 counting only the distinct ones).

The product of its (nonzero) digits is 2240, while the sum is 27.

The square root of 87405021 is about 9349.0652473924. The cubic root of 87405021 is about 443.7913098883.

Adding to 87405021 its reverse (12050478), we get a palindrome (99455499).

The spelling of 87405021 in words is "eighty-seven million, four hundred five thousand, twenty-one".