21432765 has 8 divisors (see below), whose sum is σ = 34292448. Its totient is φ = 11430800.

The previous prime is 21432751. The next prime is 21432781. The reversal of 21432765 is 56723412.

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

It is not a de Polignac number, because 21432765 - 2⁶ = 21432701 is a prime.

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

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 714411 + ... + 714440.

It is an arithmetic number, because the mean of its divisors is an integer number (4286556).

Almost surely, 2^21432765 is an apocalyptic number.

It is an amenable number.

21432765 is a deficient number, since it is larger than the sum of its proper divisors (12859683).

21432765 is a wasteful number, since it uses less digits than its factorization.

21432765 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1428859.

The product of its digits is 10080, while the sum is 30.

The square root of 21432765 is about 4629.5534341878. The cubic root of 21432765 is about 277.7747299517.

The spelling of 21432765 in words is "twenty-one million, four hundred thirty-two thousand, seven hundred sixty-five".