100721345 has 8 divisors (see below), whose sum is σ = 127975464. Its totient is φ = 75837184.

The previous prime is 100721339. The next prime is 100721353. The reversal of 100721345 is 543127001.

It can be written as a sum of positive squares in 4 ways, for example, as 2334784 + 98386561 = 1528^2 + 9919^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 100721345 - 2⁶ = 100721281 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 100721345.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 592394 + ... + 592563.

It is an arithmetic number, because the mean of its divisors is an integer number (15996933).

Almost surely, 2^100721345 is an apocalyptic number.

It is an amenable number.

100721345 is a deficient number, since it is larger than the sum of its proper divisors (27254119).

100721345 is a wasteful number, since it uses less digits than its factorization.

100721345 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1184979.

The product of its (nonzero) digits is 840, while the sum is 23.

The square root of 100721345 is about 10036.0024412113. The cubic root of 100721345 is about 465.2722728100.

Adding to 100721345 its reverse (543127001), we get a palindrome (643848346).

The spelling of 100721345 in words is "one hundred million, seven hundred twenty-one thousand, three hundred forty-five".