20723739840 has 672 divisors, whose sum is σ = 79862013504. Its totient is φ = 5096079360.

The previous prime is 20723739833. The next prime is 20723739871. The reversal of 20723739840 is 4893732702.

20723739840 is a `hidden beast` number, since 20 + 7 + 237 + 398 + 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 an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 80636992 + ... + 80637248.

It is an arithmetic number, because the mean of its divisors is an integer number (118842282).

Almost surely, 2^20723739840 is an apocalyptic number.

20723739840 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 20723739840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39931006752).

20723739840 is an abundant number, since it is smaller than the sum of its proper divisors (59138273664).

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

20723739840 is a wasteful number, since it uses less digits than its factorization.

20723739840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 367 (or 345 counting only the distinct ones).

The product of its (nonzero) digits is 508032, while the sum is 45.

The spelling of 20723739840 in words is "twenty billion, seven hundred twenty-three million, seven hundred thirty-nine thousand, eight hundred forty".