20809974 has 8 divisors (see below), whose sum is σ = 41619960. Its totient is φ = 6936656.

The previous prime is 20809961. The next prime is 20809991. The reversal of 20809974 is 47990802.

It is a sphenic number, since it is the product of 3 distinct primes.

20809974 is an admirable number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1734159 + ... + 1734170.

It is an arithmetic number, because the mean of its divisors is an integer number (5202495).

Almost surely, 2^20809974 is an apocalyptic number.

20809974 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20809974 is a wasteful number, since it uses less digits than its factorization.

20809974 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3468334.

The product of its (nonzero) digits is 36288, while the sum is 39.

The square root of 20809974 is about 4561.7950414283. The cubic root of 20809974 is about 275.0577245215.

The spelling of 20809974 in words is "twenty million, eight hundred nine thousand, nine hundred seventy-four".