21464749 has 4 divisors (see below), whose sum is σ = 21621564. Its totient is φ = 21307936.

The previous prime is 21464719. The next prime is 21464777. The reversal of 21464749 is 94746412.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 6200100 + 15264649 = 2490^2 + 3907^2 .

It is a cyclic number.

It is not a de Polignac number, because 21464749 - 2⁵ = 21464717 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21464719) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 78202 + ... + 78475.

It is an arithmetic number, because the mean of its divisors is an integer number (5405391).

Almost surely, 2^21464749 is an apocalyptic number.

It is an amenable number.

21464749 is a deficient number, since it is larger than the sum of its proper divisors (156815).

21464749 is a wasteful number, since it uses less digits than its factorization.

21464749 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 156814.

The product of its digits is 48384, while the sum is 37.

The square root of 21464749 is about 4633.0064752815. The cubic root of 21464749 is about 277.9128351887.

The spelling of 21464749 in words is "twenty-one million, four hundred sixty-four thousand, seven hundred forty-nine".