20400140 has 12 divisors (see below), whose sum is σ = 42840336. Its totient is φ = 8160048.

The previous prime is 20400101. The next prime is 20400151. The reversal of 20400140 is 4100402.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 509984 + ... + 510023.

It is an arithmetic number, because the mean of its divisors is an integer number (3570028).

Almost surely, 2^20400140 is an apocalyptic number.

20400140 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20400140 is an abundant number, since it is smaller than the sum of its proper divisors (22440196).

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

20400140 is a wasteful number, since it uses less digits than its factorization.

20400140 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1020016 (or 1020014 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 11.

The square root of 20400140 is about 4516.6514144884. The cubic root of 20400140 is about 273.2400666656.

Adding to 20400140 its reverse (4100402), we get a palindrome (24500542).

The spelling of 20400140 in words is "twenty million, four hundred thousand, one hundred forty".