21740690 has 16 divisors (see below), whose sum is σ = 39191040. Its totient is φ = 8683440.

The previous prime is 21740687. The next prime is 21740711. The reversal of 21740690 is 9604712.

It is a super-2 number, since 2×21740690² = 945315203352200, which contains 22 as substring.

It is a Curzon number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 8591 + ... + 10829.

It is an arithmetic number, because the mean of its divisors is an integer number (2449440).

Almost surely, 2^21740690 is an apocalyptic number.

21740690 is a deficient number, since it is larger than the sum of its proper divisors (17450350).

21740690 is a wasteful number, since it uses less digits than its factorization.

21740690 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3217.

The product of its (nonzero) digits is 3024, while the sum is 29.

The square root of 21740690 is about 4662.6912829395. The cubic root of 21740690 is about 279.0986748603.

The spelling of 21740690 in words is "twenty-one million, seven hundred forty thousand, six hundred ninety".