21519754 has 4 divisors (see below), whose sum is σ = 32279634. Its totient is φ = 10759876.

The previous prime is 21519727. The next prime is 21519791. The reversal of 21519754 is 45791512.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 20043529 + 1476225 = 4477^2 + 1215^2 .

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 as a sum of consecutive naturals, namely, 5379937 + ... + 5379940.

Almost surely, 2^21519754 is an apocalyptic number.

21519754 is a deficient number, since it is larger than the sum of its proper divisors (10759880).

21519754 is a wasteful number, since it uses less digits than its factorization.

21519754 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10759879.

The product of its digits is 12600, while the sum is 34.

The square root of 21519754 is about 4638.9388872888. The cubic root of 21519754 is about 278.1500234019.

The spelling of 21519754 in words is "twenty-one million, five hundred nineteen thousand, seven hundred fifty-four".