20907072 has 140 divisors (see below), whose sum is σ = 64234060. Its totient is φ = 6718464.

The previous prime is 20907067. The next prime is 20907077. The reversal of 20907072 is 27070902.

It is an interprime number because it is at equal distance from previous prime (20907067) and next prime (20907077).

It can be written as a sum of positive squares in 2 ways, for example, as 16842816 + 4064256 = 4104^2 + 2016^2 .

It is a super-2 number, since 2×20907072² = 874211319226368, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20907077) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 191754 + ... + 191862.

Almost surely, 2^20907072 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 20907072, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32117030).

20907072 is an abundant number, since it is smaller than the sum of its proper divisors (43326988).

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

20907072 is a wasteful number, since it uses less digits than its factorization.

20907072 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 170 (or 151 counting only the distinct ones).

The product of its (nonzero) digits is 1764, while the sum is 27.

The square root of 20907072 is about 4572.4251770805. The cubic root of 20907072 is about 275.4848614271.

Adding to 20907072 its reverse (27070902), we get a palindrome (47977974).

The spelling of 20907072 in words is "twenty million, nine hundred seven thousand, seventy-two".