20921774 has 16 divisors (see below), whose sum is σ = 33140880. Its totient is φ = 9878400.

The previous prime is 20921773. The next prime is 20921777. The reversal of 20921774 is 47712902.

It is a self number, because there is not a number n which added to its sum of digits gives 20921774.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20921773) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14552 + ... + 15924.

It is an arithmetic number, because the mean of its divisors is an integer number (2071305).

Almost surely, 2^20921774 is an apocalyptic number.

20921774 is a deficient number, since it is larger than the sum of its proper divisors (12219106).

20921774 is a wasteful number, since it uses less digits than its factorization.

20921774 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1795.

The product of its (nonzero) digits is 7056, while the sum is 32.

The square root of 20921774 is about 4574.0325753103. The cubic root of 20921774 is about 275.5494205937.

The spelling of 20921774 in words is "twenty million, nine hundred twenty-one thousand, seven hundred seventy-four".