21747349 has 4 divisors (see below), whose sum is σ = 23420236. Its totient is φ = 20074464.

The previous prime is 21747347. The next prime is 21747359. The reversal of 21747349 is 94374712.

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 14554225 + 7193124 = 3815^2 + 2682^2 .

It is a cyclic number.

It is not a de Polignac number, because 21747349 - 2¹ = 21747347 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 (21747347) 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, 836424 + ... + 836449.

It is an arithmetic number, because the mean of its divisors is an integer number (5855059).

Almost surely, 2^21747349 is an apocalyptic number.

It is an amenable number.

21747349 is a deficient number, since it is larger than the sum of its proper divisors (1672887).

21747349 is a wasteful number, since it uses less digits than its factorization.

21747349 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1672886.

The product of its digits is 42336, while the sum is 37.

The square root of 21747349 is about 4663.4053008504. The cubic root of 21747349 is about 279.1271671844.

The spelling of 21747349 in words is "twenty-one million, seven hundred forty-seven thousand, three hundred forty-nine".