21087495 has 96 divisors (see below), whose sum is σ = 44815680. Its totient is φ = 9031680.

The previous prime is 21087491. The next prime is 21087529. The reversal of 21087495 is 59478012.

It is not a de Polignac number, because 21087495 - 2² = 21087491 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21087491) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 186559 + ... + 186671.

It is an arithmetic number, because the mean of its divisors is an integer number (466830).

Almost surely, 2^21087495 is an apocalyptic number.

21087495 is an abundant number, since it is smaller than the sum of its proper divisors (23728185).

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

21087495 is a wasteful number, since it uses less digits than its factorization.

21087495 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 177 (or 174 counting only the distinct ones).

The product of its (nonzero) digits is 20160, while the sum is 36.

The square root of 21087495 is about 4592.1122590808. The cubic root of 21087495 is about 276.2750487445.

The spelling of 21087495 in words is "twenty-one million, eighty-seven thousand, four hundred ninety-five".