21740949 has 18 divisors (see below), whose sum is σ = 32079606. Its totient is φ = 14184720.

The previous prime is 21740903. The next prime is 21740963. The reversal of 21740949 is 94904712.

It can be written as a sum of positive squares in only one way, i.e., 12830724 + 8910225 = 3582^2 + 2985^2 .

It is not a de Polignac number, because 21740949 - 2¹¹ = 21738901 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21740249) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 109152 + ... + 109350.

Almost surely, 2^21740949 is an apocalyptic number.

It is an amenable number.

21740949 is a deficient number, since it is larger than the sum of its proper divisors (10338657).

21740949 is an equidigital number, since it uses as much as digits as its factorization.

21740949 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 465 (or 263 counting only the distinct ones).

The product of its (nonzero) digits is 18144, while the sum is 36.

The square root of 21740949 is about 4662.7190565163. The cubic root of 21740949 is about 279.0997831702.

The spelling of 21740949 in words is "twenty-one million, seven hundred forty thousand, nine hundred forty-nine".