20906997 has 4 divisors (see below), whose sum is σ = 27876000. Its totient is φ = 13937996.

The previous prime is 20906971. The next prime is 20907001. The reversal of 20906997 is 79960902.

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 not a de Polignac number, because 20906997 - 2⁶ = 20906933 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20906917) 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, 3484497 + ... + 3484502.

It is an arithmetic number, because the mean of its divisors is an integer number (6969000).

Almost surely, 2^20906997 is an apocalyptic number.

It is an amenable number.

20906997 is a deficient number, since it is larger than the sum of its proper divisors (6969003).

20906997 is an equidigital number, since it uses as much as digits as its factorization.

20906997 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6969002.

The product of its (nonzero) digits is 61236, while the sum is 42.

The square root of 20906997 is about 4572.4169757361. The cubic root of 20906997 is about 275.4845320108.

The spelling of 20906997 in words is "twenty million, nine hundred six thousand, nine hundred ninety-seven".