21732538 has 8 divisors (see below), whose sum is σ = 33045588. Its totient is φ = 10717344.

The previous prime is 21732533. The next prime is 21732547. The reversal of 21732538 is 83523712.

It can be written as a sum of positive squares in 2 ways, for example, as 20766249 + 966289 = 4557^2 + 983^2 .

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

It is not an unprimeable number, because it can be changed into a prime (21732533) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 74281 + ... + 74572.

Almost surely, 2^21732538 is an apocalyptic number.

21732538 is a deficient number, since it is larger than the sum of its proper divisors (11313050).

21732538 is a wasteful number, since it uses less digits than its factorization.

21732538 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 148928.

The product of its digits is 10080, while the sum is 31.

The square root of 21732538 is about 4661.8170277264. The cubic root of 21732538 is about 279.0637864118.

The spelling of 21732538 in words is "twenty-one million, seven hundred thirty-two thousand, five hundred thirty-eight".