20997312 has 112 divisors (see below), whose sum is σ = 67299840. Its totient is φ = 5640192.

The previous prime is 20997311. The next prime is 20997313. The reversal of 20997312 is 21379902.

It is an interprime number because it is at equal distance from previous prime (20997311) and next prime (20997313).

It is a tau number, because it is divible by the number of its divisors (112).

It is a super-2 number, since 2×20997312² = 881774222450688, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20997311) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 22389 + ... + 23307.

Almost surely, 2^20997312 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 20997312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33649920).

20997312 is an abundant number, since it is smaller than the sum of its proper divisors (46302528).

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

20997312 is a wasteful number, since it uses less digits than its factorization.

20997312 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 958 (or 948 counting only the distinct ones).

The product of its (nonzero) digits is 6804, while the sum is 33.

The square root of 20997312 is about 4582.2824007256. The cubic root of 20997312 is about 275.8806457260.

The spelling of 20997312 in words is "twenty million, nine hundred ninety-seven thousand, three hundred twelve".