21149371 has 4 divisors (see below), whose sum is σ = 21496144. Its totient is φ = 20802600.

The previous prime is 21149353. The next prime is 21149383. The reversal of 21149371 is 17394112.

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

It is a cyclic number.

It is not a de Polignac number, because 21149371 - 2⁷ = 21149243 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21149321) 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, 173295 + ... + 173416.

It is an arithmetic number, because the mean of its divisors is an integer number (5374036).

Almost surely, 2^21149371 is an apocalyptic number.

21149371 is a deficient number, since it is larger than the sum of its proper divisors (346773).

21149371 is an equidigital number, since it uses as much as digits as its factorization.

21149371 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 346772.

The product of its digits is 1512, while the sum is 28.

The square root of 21149371 is about 4598.8445287920. The cubic root of 21149371 is about 276.5450049750.

The spelling of 21149371 in words is "twenty-one million, one hundred forty-nine thousand, three hundred seventy-one".