21491422 has 4 divisors (see below), whose sum is σ = 32237136. Its totient is φ = 10745710.

The previous prime is 21491411. The next prime is 21491423. The reversal of 21491422 is 22419412.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21491423) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5372854 + ... + 5372857.

It is an arithmetic number, because the mean of its divisors is an integer number (8059284).

Almost surely, 2^21491422 is an apocalyptic number.

21491422 is a deficient number, since it is larger than the sum of its proper divisors (10745714).

21491422 is a wasteful number, since it uses less digits than its factorization.

21491422 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10745713.

The product of its digits is 1152, while the sum is 25.

The square root of 21491422 is about 4635.8841659386. The cubic root of 21491422 is about 278.0279029322.

The spelling of 21491422 in words is "twenty-one million, four hundred ninety-one thousand, four hundred twenty-two".