21474749 has 4 divisors (see below), whose sum is σ = 21511200. Its totient is φ = 21438300.

The previous prime is 21474737. The next prime is 21474751. The reversal of 21474749 is 94747412.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21474749 - 2¹² = 21470653 is a prime.

It is a super-2 number, since 2×21474749² = 922329689226002, which contains 22 as substring.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21474799) 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, 17327 + ... + 18524.

It is an arithmetic number, because the mean of its divisors is an integer number (5377800).

Almost surely, 2^21474749 is an apocalyptic number.

It is an amenable number.

21474749 is a deficient number, since it is larger than the sum of its proper divisors (36451).

21474749 is an equidigital number, since it uses as much as digits as its factorization.

21474749 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36450.

The product of its digits is 56448, while the sum is 38.

The square root of 21474749 is about 4634.0855624384. The cubic root of 21474749 is about 277.9559865107.

The spelling of 21474749 in words is "twenty-one million, four hundred seventy-four thousand, seven hundred forty-nine".