106721645 has 8 divisors (see below), whose sum is σ = 128189304. Its totient is φ = 85295104.

The previous prime is 106721611. The next prime is 106721683. The reversal of 106721645 is 546127601.

It can be written as a sum of positive squares in 4 ways, for example, as 14600041 + 92121604 = 3821^2 + 9598^2 .

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 106721645 - 2⁶ = 106721581 is a prime.

It is a super-3 number, since 3×106721645³ (a number of 25 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

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, 4244 + ... + 15213.

It is an arithmetic number, because the mean of its divisors is an integer number (16023663).

Almost surely, 2^106721645 is an apocalyptic number.

It is an amenable number.

106721645 is a deficient number, since it is larger than the sum of its proper divisors (21467659).

106721645 is a wasteful number, since it uses less digits than its factorization.

106721645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20559.

The product of its (nonzero) digits is 10080, while the sum is 32.

The square root of 106721645 is about 10330.6168741271. The cubic root of 106721645 is about 474.3339066312. Note that the first 3 decimals are identical.

The spelling of 106721645 in words is "one hundred six million, seven hundred twenty-one thousand, six hundred forty-five".