21147922 has 4 divisors (see below), whose sum is σ = 31721886. Its totient is φ = 10573960.

The previous prime is 21147869. The next prime is 21147937. The reversal of 21147922 is 22974112.

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., 18584721 + 2563201 = 4311^2 + 1601^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5286979 + ... + 5286982.

Almost surely, 2^21147922 is an apocalyptic number.

21147922 is a deficient number, since it is larger than the sum of its proper divisors (10573964).

21147922 is a wasteful number, since it uses less digits than its factorization.

21147922 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10573963.

The product of its digits is 2016, while the sum is 28.

The square root of 21147922 is about 4598.6869865213. The cubic root of 21147922 is about 276.5386892180.

The spelling of 21147922 in words is "twenty-one million, one hundred forty-seven thousand, nine hundred twenty-two".