21149611 has 4 divisors (see below), whose sum is σ = 24170992. Its totient is φ = 18128232.

The previous prime is 21149599. The next prime is 21149617. The reversal of 21149611 is 11694112.

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 21149611 - 2¹⁷ = 21018539 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21149617) 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, 1510680 + ... + 1510693.

It is an arithmetic number, because the mean of its divisors is an integer number (6042748).

Almost surely, 2^21149611 is an apocalyptic number.

21149611 is a deficient number, since it is larger than the sum of its proper divisors (3021381).

21149611 is an equidigital number, since it uses as much as digits as its factorization.

21149611 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3021380.

The product of its digits is 432, while the sum is 25.

The square root of 21149611 is about 4598.8706222289. The cubic root of 21149611 is about 276.5460510353.

The spelling of 21149611 in words is "twenty-one million, one hundred forty-nine thousand, six hundred eleven".