20891472 has 80 divisors (see below), whose sum is σ = 62412672. Its totient is φ = 5898240.

The previous prime is 20891461. The next prime is 20891473. The reversal of 20891472 is 27419802.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20891473) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 32272 + ... + 32912.

Almost surely, 2^20891472 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 20891472, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31206336).

20891472 is an abundant number, since it is smaller than the sum of its proper divisors (41521200).

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

20891472 is a wasteful number, since it uses less digits than its factorization.

20891472 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 756 (or 750 counting only the distinct ones).

The product of its (nonzero) digits is 8064, while the sum is 33.

The square root of 20891472 is about 4570.7189806419. The cubic root of 20891472 is about 275.4163258749.

The spelling of 20891472 in words is "twenty million, eight hundred ninety-one thousand, four hundred seventy-two".