20407680 has 128 divisors (see below), whose sum is σ = 72338400. Its totient is φ = 5437440.

The previous prime is 20407679. The next prime is 20407711. The reversal of 20407680 is 8670402.

20407680 = 145² + 146² + ... + 400².

It is a tau number, because it is divible by the number of its divisors (128).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16690 + ... + 17870.

Almost surely, 2^20407680 is an apocalyptic number.

20407680 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 20407680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36169200).

20407680 is an abundant number, since it is smaller than the sum of its proper divisors (51930720).

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

20407680 is a wasteful number, since it uses less digits than its factorization.

20407680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1209 (or 1191 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 27.

The square root of 20407680 is about 4517.4860265418. The cubic root of 20407680 is about 273.2737261785.

The spelling of 20407680 in words is "twenty million, four hundred seven thousand, six hundred eighty".