20909772 has 96 divisors (see below), whose sum is σ = 59693760. Its totient is φ = 6289920.

The previous prime is 20909771. The next prime is 20909789. The reversal of 20909772 is 27790902.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (20909771) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 74272 + ... + 74552.

It is an arithmetic number, because the mean of its divisors is an integer number (621810).

Almost surely, 2^20909772 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20909772, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29846880).

20909772 is an abundant number, since it is smaller than the sum of its proper divisors (38783988).

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

20909772 is a wasteful number, since it uses less digits than its factorization.

20909772 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 360 (or 352 counting only the distinct ones).

The product of its (nonzero) digits is 15876, while the sum is 36.

The square root of 20909772 is about 4572.7204156826. The cubic root of 20909772 is about 275.4967198883.

The spelling of 20909772 in words is "twenty million, nine hundred nine thousand, seven hundred seventy-two".