20879432640 has 448 divisors, whose sum is σ = 85087480320. Its totient is φ = 4763566080.

The previous prime is 20879432617. The next prime is 20879432647. The reversal of 20879432640 is 4623497802.

20879432640 is a `hidden beast` number, since 208 + 7 + 9 + 432 + 6 + 4 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20879432647) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1609219 + ... + 1622141.

Almost surely, 2^20879432640 is an apocalyptic number.

20879432640 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 20879432640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (42543740160).

20879432640 is an abundant number, since it is smaller than the sum of its proper divisors (64208047680).

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

20879432640 is a wasteful number, since it uses less digits than its factorization.

20879432640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12977 (or 12961 counting only the distinct ones).

The product of its (nonzero) digits is 580608, while the sum is 45.

The spelling of 20879432640 in words is "twenty billion, eight hundred seventy-nine million, four hundred thirty-two thousand, six hundred forty".