21432587 has 8 divisors (see below), whose sum is σ = 23414832. Its totient is φ = 19456000.

The previous prime is 21432571. The next prime is 21432599. The reversal of 21432587 is 78523412.

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 21432587 - 2⁴ = 21432571 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21432547) 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, 12587 + ... + 14187.

It is an arithmetic number, because the mean of its divisors is an integer number (2926854).

Almost surely, 2^21432587 is an apocalyptic number.

21432587 is a deficient number, since it is larger than the sum of its proper divisors (1982245).

21432587 is a wasteful number, since it uses less digits than its factorization.

21432587 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2829.

The product of its digits is 13440, while the sum is 32.

The square root of 21432587 is about 4629.5342098315. The cubic root of 21432587 is about 277.7739609727.

Adding to 21432587 its reverse (78523412), we get a palindrome (99955999).

It can be divided in two parts, 214325 and 87, that added together give a palindrome (214412).

The spelling of 21432587 in words is "twenty-one million, four hundred thirty-two thousand, five hundred eighty-seven".