21432087 has 32 divisors (see below), whose sum is σ = 34292160. Its totient is φ = 13178880.

The previous prime is 21432079. The next prime is 21432091. The reversal of 21432087 is 78023412.

It is not a de Polignac number, because 21432087 - 2³ = 21432079 is a prime.

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

It is a self number, because there is not a number n which added to its sum of digits gives 21432087.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21432077) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 23887 + ... + 24767.

It is an arithmetic number, because the mean of its divisors is an integer number (1071630).

Almost surely, 2^21432087 is an apocalyptic number.

21432087 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

21432087 is a deficient number, since it is larger than the sum of its proper divisors (12860073).

21432087 is a wasteful number, since it uses less digits than its factorization.

21432087 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 960 (or 954 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 27.

The square root of 21432087 is about 4629.4802084035. The cubic root of 21432087 is about 277.7718008966.

Adding to 21432087 its reverse (78023412), we get a palindrome (99455499).

The spelling of 21432087 in words is "twenty-one million, four hundred thirty-two thousand, eighty-seven".