20897280 has 120 divisors (see below), whose sum is σ = 72452952. Its totient is φ = 5566464.

The previous prime is 20897273. The next prime is 20897287. The reversal of 20897280 is 8279802.

It is an interprime number because it is at equal distance from previous prime (20897273) and next prime (20897287).

It is a tau number, because it is divible by the number of its divisors (120).

It is a super-2 number, since 2×20897280² = 873392622796800, which contains 22 as substring.

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 (20897287) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 22587 + ... + 23493.

Almost surely, 2^20897280 is an apocalyptic number.

20897280 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 20897280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36226476).

20897280 is an abundant number, since it is smaller than the sum of its proper divisors (51555672).

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

20897280 is an equidigital number, since it uses as much as digits as its factorization.

20897280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 936 (or 917 counting only the distinct ones).

The product of its (nonzero) digits is 16128, while the sum is 36.

The square root of 20897280 is about 4571.3542851107. The cubic root of 20897280 is about 275.4418461735.

The spelling of 20897280 in words is "twenty million, eight hundred ninety-seven thousand, two hundred eighty".