20402688 has 80 divisors (see below), whose sum is σ = 55978560. Its totient is φ = 6598656.

The previous prime is 20402687. The next prime is 20402693. The reversal of 20402688 is 88620402.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (20402687) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 56653 + ... + 57011.

It is an arithmetic number, because the mean of its divisors is an integer number (699732).

Almost surely, 2^20402688 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 20402688, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27989280).

20402688 is an abundant number, since it is smaller than the sum of its proper divisors (35575872).

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

20402688 is an equidigital number, since it uses as much as digits as its factorization.

20402688 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 417 (or 401 counting only the distinct ones).

The product of its (nonzero) digits is 6144, while the sum is 30.

The square root of 20402688 is about 4516.9334730545. The cubic root of 20402688 is about 273.2514421873.

The spelling of 20402688 in words is "twenty million, four hundred two thousand, six hundred eighty-eight".