20402440040 has 64 divisors (see below), whose sum is σ = 46874918160. Its totient is φ = 7990272000.

The previous prime is 20402439997. The next prime is 20402440067. The reversal of 20402440040 is 4004420402.

It can be written as a sum of positive squares in 8 ways, for example, as 13638035524 + 6764404516 = 116782^2 + 82246^2 .

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 20402439994 and 20402440021.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 374540 + ... + 425540.

Almost surely, 2^20402440040 is an apocalyptic number.

20402440040 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 20402440040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23437459080).

20402440040 is an abundant number, since it is smaller than the sum of its proper divisors (26472478120).

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

20402440040 is a wasteful number, since it uses less digits than its factorization.

20402440040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51222 (or 51218 counting only the distinct ones).

The product of its (nonzero) digits is 1024, while the sum is 20.

Adding to 20402440040 its reverse (4004420402), we get a palindrome (24406860442).

The spelling of 20402440040 in words is "twenty billion, four hundred two million, four hundred forty thousand, forty".