21709234 has 8 divisors (see below), whose sum is σ = 32583708. Its totient is φ = 10848000.

The previous prime is 21709211. The next prime is 21709271. The reversal of 21709234 is 43290712.

It can be written as a sum of positive squares in 2 ways, for example, as 19316025 + 2393209 = 4395^2 + 1547^2 .

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4194 + ... + 7810.

Almost surely, 2^21709234 is an apocalyptic number.

21709234 is a deficient number, since it is larger than the sum of its proper divisors (10874474).

21709234 is a wasteful number, since it uses less digits than its factorization.

21709234 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6620.

The product of its (nonzero) digits is 3024, while the sum is 28.

The square root of 21709234 is about 4659.3169027230. The cubic root of 21709234 is about 278.9640031838.

Adding to 21709234 its reverse (43290712), we get a palindrome (64999946).

The spelling of 21709234 in words is "twenty-one million, seven hundred nine thousand, two hundred thirty-four".