20751377640 has 128 divisors (see below), whose sum is σ = 71205246720. Its totient is φ = 4739328000.

The previous prime is 20751377629. The next prime is 20751377701. The reversal of 20751377640 is 4677315702.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a junction number, because it is equal to n+sod(n) for n = 20751377592 and 20751377601.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1100290 + ... + 1118990.

It is an arithmetic number, because the mean of its divisors is an integer number (556290990).

Almost surely, 2^20751377640 is an apocalyptic number.

20751377640 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 20751377640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35602623360).

20751377640 is an abundant number, since it is smaller than the sum of its proper divisors (50453869080).

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

20751377640 is a wasteful number, since it uses less digits than its factorization.

20751377640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20043 (or 20039 counting only the distinct ones).

The product of its (nonzero) digits is 246960, while the sum is 42.

The spelling of 20751377640 in words is "twenty billion, seven hundred fifty-one million, three hundred seventy-seven thousand, six hundred forty".