21771299 has 4 divisors (see below), whose sum is σ = 23750520. Its totient is φ = 19792080.

The previous prime is 21771251. The next prime is 21771307. The reversal of 21771299 is 99217712.

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

It is not a de Polignac number, because 21771299 - 2¹² = 21767203 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21371299) 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, 989594 + ... + 989615.

It is an arithmetic number, because the mean of its divisors is an integer number (5937630).

Almost surely, 2^21771299 is an apocalyptic number.

21771299 is a deficient number, since it is larger than the sum of its proper divisors (1979221).

21771299 is a wasteful number, since it uses less digits than its factorization.

21771299 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1979220.

The product of its digits is 15876, while the sum is 38.

The square root of 21771299 is about 4665.9724602702. The cubic root of 21771299 is about 279.2295956550.

The spelling of 21771299 in words is "twenty-one million, seven hundred seventy-one thousand, two hundred ninety-nine".