20402323440 has 80 divisors (see below), whose sum is σ = 63838378368. Its totient is φ = 5389765888.

The previous prime is 20402323423. The next prime is 20402323523. The reversal of 20402323440 is 4432320402.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 20402323440.

It is a congruent number.

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, 371562 + ... + 422921.

Almost surely, 2^20402323440 is an apocalyptic number.

20402323440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20402323440 is an abundant number, since it is smaller than the sum of its proper divisors (43436054928).

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

20402323440 is a wasteful number, since it uses less digits than its factorization.

20402323440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 794606 (or 794600 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 24.

Adding to 20402323440 its reverse (4432320402), we get a palindrome (24834643842).

The spelling of 20402323440 in words is "twenty billion, four hundred two million, three hundred twenty-three thousand, four hundred forty".