20475840 has 224 divisors, whose sum is σ = 81345024. Its totient is φ = 4239360.

The previous prime is 20475839. The next prime is 20475853. The reversal of 20475840 is 4857402.

It is a tau number, because it is divible by the number of its divisors (224).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 20475798 and 20475807.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 73782 + ... + 74058.

Almost surely, 2^20475840 is an apocalyptic number.

20475840 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 20475840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40672512).

20475840 is an abundant number, since it is smaller than the sum of its proper divisors (60869184).

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

20475840 is a wasteful number, since it uses less digits than its factorization.

20475840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 315 (or 305 counting only the distinct ones).

The product of its (nonzero) digits is 8960, while the sum is 30.

The square root of 20475840 is about 4525.0237568437. The cubic root of 20475840 is about 273.5776254744.

It can be divided in two parts, 2047 and 5840, that added together give a palindrome (7887).

The spelling of 20475840 in words is "twenty million, four hundred seventy-five thousand, eight hundred forty".