20997180 has 72 divisors (see below), whose sum is σ = 64183392. Its totient is φ = 5556096.

The previous prime is 20997149. The next prime is 20997181. The reversal of 20997180 is 8179902.

It is a happy number.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20997181) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 27889 + ... + 28631.

It is an arithmetic number, because the mean of its divisors is an integer number (891436).

Almost surely, 2^20997180 is an apocalyptic number.

20997180 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20997180, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32091696).

20997180 is an abundant number, since it is smaller than the sum of its proper divisors (43186212).

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

20997180 is a wasteful number, since it uses less digits than its factorization.

20997180 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 915 (or 910 counting only the distinct ones).

The product of its (nonzero) digits is 9072, while the sum is 36.

The square root of 20997180 is about 4582.2679974004. The cubic root of 20997180 is about 275.8800676152.

The spelling of 20997180 in words is "twenty million, nine hundred ninety-seven thousand, one hundred eighty".