100721718 has 20 divisors (see below), whose sum is σ = 225691620. Its totient is φ = 33573852.

The previous prime is 100721711. The next prime is 100721729. The reversal of 100721718 is 817127001.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a junction number, because it is equal to n+sod(n) for n = 100721691 and 100721700.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (100721711) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 310708 + ... + 311031.

It is an arithmetic number, because the mean of its divisors is an integer number (11284581).

Almost surely, 2^100721718 is an apocalyptic number.

100721718 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

100721718 is an abundant number, since it is smaller than the sum of its proper divisors (124969902).

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

100721718 is an equidigital number, since it uses as much as digits as its factorization.

100721718 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 621753 (or 621744 counting only the distinct ones).

The product of its (nonzero) digits is 784, while the sum is 27.

The square root of 100721718 is about 10036.0210242905. The cubic root of 100721718 is about 465.2728471548.

Adding to 100721718 its reverse (817127001), we get a palindrome (917848719).

The spelling of 100721718 in words is "one hundred million, seven hundred twenty-one thousand, seven hundred eighteen".