20391072 has 48 divisors (see below), whose sum is σ = 57647520. Its totient is φ = 6273792.

The previous prime is 20391071. The next prime is 20391101. The reversal of 20391072 is 27019302.

It is a tau number, because it is divible by the number of its divisors (48).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is not an unprimeable number, because it can be changed into a prime (20391071) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6922 + ... + 9417.

It is an arithmetic number, because the mean of its divisors is an integer number (1200990).

Almost surely, 2^20391072 is an apocalyptic number.

It is an amenable number.

20391072 is an abundant number, since it is smaller than the sum of its proper divisors (37256448).

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

20391072 is a wasteful number, since it uses less digits than its factorization.

20391072 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16365 (or 16357 counting only the distinct ones).

The product of its (nonzero) digits is 756, while the sum is 24.

The square root of 20391072 is about 4515.6474618819. The cubic root of 20391072 is about 273.1995749804.

The spelling of 20391072 in words is "twenty million, three hundred ninety-one thousand, seventy-two".