20691337 has 4 divisors (see below), whose sum is σ = 20798740. Its totient is φ = 20583936.

The previous prime is 20691331. The next prime is 20691371. The reversal of 20691337 is 73319602.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 73319602 = 2 ⋅36659801.

It can be written as a sum of positive squares in 2 ways, for example, as 1498176 + 19193161 = 1224^2 + 4381^2 .

It is a cyclic number.

It is not a de Polignac number, because 20691337 - 2²³ = 12302729 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20691299 and 20691308.

It is not an unprimeable number, because it can be changed into a prime (20691331) 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, 53412 + ... + 53797.

It is an arithmetic number, because the mean of its divisors is an integer number (5199685).

Almost surely, 2^20691337 is an apocalyptic number.

It is an amenable number.

20691337 is a deficient number, since it is larger than the sum of its proper divisors (107403).

20691337 is a wasteful number, since it uses less digits than its factorization.

20691337 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 107402.

The product of its (nonzero) digits is 6804, while the sum is 31.

The square root of 20691337 is about 4548.7731312960. The cubic root of 20691337 is about 274.5340296209.

The spelling of 20691337 in words is "twenty million, six hundred ninety-one thousand, three hundred thirty-seven".