21734509 has 8 divisors (see below), whose sum is σ = 22172472. Its totient is φ = 21300480.

The previous prime is 21734501. The next prime is 21734519. The reversal of 21734509 is 90543712.

It can be written as a sum of positive squares in 4 ways, for example, as 10989225 + 10745284 = 3315^2 + 3278^2 .

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 21734509 - 2³ = 21734501 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21734501) by changing a digit.

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, 11769 + ... + 13489.

It is an arithmetic number, because the mean of its divisors is an integer number (2771559).

Almost surely, 2^21734509 is an apocalyptic number.

It is an amenable number.

21734509 is a deficient number, since it is larger than the sum of its proper divisors (437963).

21734509 is a wasteful number, since it uses less digits than its factorization.

21734509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1967.

The product of its (nonzero) digits is 7560, while the sum is 31.

The square root of 21734509 is about 4662.0284211918. The cubic root of 21734509 is about 279.0722225808.

The spelling of 21734509 in words is "twenty-one million, seven hundred thirty-four thousand, five hundred nine".