20897408 has 64 divisors (see below), whose sum is σ = 48323520. Its totient is φ = 8816640.

The previous prime is 20897377. The next prime is 20897411. The reversal of 20897408 is 80479802.

It is a tau number, because it is divible by the number of its divisors (64).

It is a super-2 number, since 2×20897408² = 873403322236928, which contains 22 as substring.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 74228 + ... + 74508.

It is an arithmetic number, because the mean of its divisors is an integer number (755055).

Almost surely, 2^20897408 is an apocalyptic number.

20897408 is a gapful number since it is divisible by the number (28) 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 20897408, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24161760).

20897408 is an abundant number, since it is smaller than the sum of its proper divisors (27426112).

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

20897408 is an equidigital number, since it uses as much as digits as its factorization.

20897408 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 385 (or 373 counting only the distinct ones).

The product of its (nonzero) digits is 32256, while the sum is 38.

The square root of 20897408 is about 4571.3682853168. The cubic root of 20897408 is about 275.4424085510.

The spelling of 20897408 in words is "twenty million, eight hundred ninety-seven thousand, four hundred eight".