21972826 has 4 divisors (see below), whose sum is σ = 32959242. Its totient is φ = 10986412.

The previous prime is 21972809. The next prime is 21972833. The reversal of 21972826 is 62827912.

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., 17766225 + 4206601 = 4215^2 + 2051^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5493205 + ... + 5493208.

Almost surely, 2^21972826 is an apocalyptic number.

21972826 is a deficient number, since it is larger than the sum of its proper divisors (10986416).

21972826 is a wasteful number, since it uses less digits than its factorization.

21972826 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10986415.

The product of its digits is 24192, while the sum is 37.

The square root of 21972826 is about 4687.5181066317. The cubic root of 21972826 is about 280.0885179318.

The spelling of 21972826 in words is "twenty-one million, nine hundred seventy-two thousand, eight hundred twenty-six".