21740737 has 4 divisors (see below), whose sum is σ = 21866580. Its totient is φ = 21614896.

The previous prime is 21740729. The next prime is 21740753. The reversal of 21740737 is 73704712.

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 17313921 + 4426816 = 4161^2 + 2104^2 .

It is a cyclic number.

It is not a de Polignac number, because 21740737 - 2³ = 21740729 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21740699 and 21740708.

It is not an unprimeable number, because it can be changed into a prime (21740717) 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, 62662 + ... + 63007.

It is an arithmetic number, because the mean of its divisors is an integer number (5466645).

Almost surely, 2^21740737 is an apocalyptic number.

It is an amenable number.

21740737 is a deficient number, since it is larger than the sum of its proper divisors (125843).

21740737 is a wasteful number, since it uses less digits than its factorization.

21740737 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 125842.

The product of its (nonzero) digits is 8232, while the sum is 31.

The square root of 21740737 is about 4662.6963229445. The cubic root of 21740737 is about 279.0988759828.

The spelling of 21740737 in words is "twenty-one million, seven hundred forty thousand, seven hundred thirty-seven".