21942737 has 6 divisors (see below), whose sum is σ = 22312134. Its totient is φ = 21579360.

The previous prime is 21942731. The next prime is 21942751. The reversal of 21942737 is 73724912.

It can be written as a sum of positive squares in 3 ways, for example, as 30976 + 21911761 = 176^2 + 4681^2 .

It is not a de Polignac number, because 21942737 - 2⁶ = 21942673 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21942697 and 21942706.

It is not an unprimeable number, because it can be changed into a prime (21942731) 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 5 ways as a sum of consecutive naturals, for example, 773 + ... + 6669.

It is an arithmetic number, because the mean of its divisors is an integer number (3718689).

Almost surely, 2^21942737 is an apocalyptic number.

It is an amenable number.

21942737 is a deficient number, since it is larger than the sum of its proper divisors (369397).

21942737 is an frugal number, since it uses more digits than its factorization.

21942737 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6019 (or 5958 counting only the distinct ones).

The product of its digits is 21168, while the sum is 35.

The square root of 21942737 is about 4684.3075261985. The cubic root of 21942737 is about 279.9606109558.

The spelling of 21942737 in words is "twenty-one million, nine hundred forty-two thousand, seven hundred thirty-seven".