20637978984 has 320 divisors, whose sum is σ = 67361648640. Its totient is φ = 5782078080.

The previous prime is 20637978983. The next prime is 20637979003. The reversal of 20637978984 is 48987973602.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is not an unprimeable number, because it can be changed into a prime (20637978983) by changing a digit.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 76154769 + ... + 76155039.

It is an arithmetic number, because the mean of its divisors is an integer number (210505152).

Almost surely, 2^20637978984 is an apocalyptic number.

20637978984 is a gapful number since it is divisible by the number (24) 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 20637978984, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33680824320).

20637978984 is an abundant number, since it is smaller than the sum of its proper divisors (46723669656).

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

20637978984 is a wasteful number, since it uses less digits than its factorization.

20637978984 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 562 (or 549 counting only the distinct ones).

The product of its (nonzero) digits is 36578304, while the sum is 63.

The spelling of 20637978984 in words is "twenty billion, six hundred thirty-seven million, nine hundred seventy-eight thousand, nine hundred eighty-four".