100661721 has 16 divisors (see below), whose sum is σ = 136416000. Its totient is φ = 66014208.

The previous prime is 100661713. The next prime is 100661723. The reversal of 100661721 is 127166001.

It is not a de Polignac number, because 100661721 - 2³ = 100661713 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 100661691 and 100661700.

It is not an unprimeable number, because it can be changed into a prime (100661723) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 82105 + ... + 83321.

It is an arithmetic number, because the mean of its divisors is an integer number (8526000).

Almost surely, 2^100661721 is an apocalyptic number.

It is an amenable number.

100661721 is a deficient number, since it is larger than the sum of its proper divisors (35754279).

100661721 is a wasteful number, since it uses less digits than its factorization.

100661721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1648.

The product of its (nonzero) digits is 504, while the sum is 24.

The square root of 100661721 is about 10033.0314960136. The cubic root of 100661721 is about 465.1804456346.

The spelling of 100661721 in words is "one hundred million, six hundred sixty-one thousand, seven hundred twenty-one".