20909737 has 4 divisors (see below), whose sum is σ = 21818880. Its totient is φ = 20000596.

The previous prime is 20909723. The next prime is 20909741. The reversal of 20909737 is 73790902.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20909737 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20909696 and 20909705.

It is not an unprimeable number, because it can be changed into a prime (20909767) 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, 454537 + ... + 454582.

It is an arithmetic number, because the mean of its divisors is an integer number (5454720).

Almost surely, 2^20909737 is an apocalyptic number.

It is an amenable number.

20909737 is a deficient number, since it is larger than the sum of its proper divisors (909143).

20909737 is an equidigital number, since it uses as much as digits as its factorization.

20909737 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 909142.

The product of its (nonzero) digits is 23814, while the sum is 37.

The square root of 20909737 is about 4572.7165886374. The cubic root of 20909737 is about 275.4965661740.

The spelling of 20909737 in words is "twenty million, nine hundred nine thousand, seven hundred thirty-seven".