20450640 has 240 divisors, whose sum is σ = 77352192. Its totient is φ = 4451328.

The previous prime is 20450623. The next prime is 20450659. The reversal of 20450640 is 4605402.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (240).

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 435097 + ... + 435143.

Almost surely, 2^20450640 is an apocalyptic number.

20450640 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 20450640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38676096).

20450640 is an abundant number, since it is smaller than the sum of its proper divisors (56901552).

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

20450640 is a wasteful number, since it uses less digits than its factorization.

20450640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 114 (or 101 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 21.

The square root of 20450640 is about 4522.2383838095. The cubic root of 20450640 is about 273.4653470306.

The spelling of 20450640 in words is "twenty million, four hundred fifty thousand, six hundred forty".