256723172020 has 96 divisors (see below), whose sum is σ = 653468014080. Its totient is φ = 82703462400.

The previous prime is 256723172011. The next prime is 256723172059. The reversal of 256723172020 is 20271327652.

It is a congruent number.

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, 1340641 + ... + 1520119.

It is an arithmetic number, because the mean of its divisors is an integer number (6806958480).

Almost surely, 2^256723172020 is an apocalyptic number.

256723172020 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 256723172020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (326734007040).

256723172020 is an abundant number, since it is smaller than the sum of its proper divisors (396744842060).

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

256723172020 is a wasteful number, since it uses less digits than its factorization.

256723172020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 180113 (or 180111 counting only the distinct ones).

The product of its (nonzero) digits is 70560, while the sum is 37.

Adding to 256723172020 its reverse (20271327652), we get a palindrome (276994499672).

The spelling of 256723172020 in words is "two hundred fifty-six billion, seven hundred twenty-three million, one hundred seventy-two thousand, twenty".