105423721 has 12 divisors (see below), whose sum is σ = 114579228. Its totient is φ = 96954624.

The previous prime is 105423701. The next prime is 105423779. The reversal of 105423721 is 127324501.

It is a happy number.

It can be written as a sum of positive squares in 6 ways, for example, as 35868121 + 69555600 = 5989^2 + 8340^2 .

It is not a de Polignac number, because 105423721 - 2¹⁵ = 105390953 is a prime.

It is a super-4 number, since 4×105423721⁴ (a number of 33 digits) contains 4444 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (105423701) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 51901 + ... + 53893.

It is an arithmetic number, because the mean of its divisors is an integer number (9548269).

Almost surely, 2^105423721 is an apocalyptic number.

It is an amenable number.

105423721 is a deficient number, since it is larger than the sum of its proper divisors (9155507).

105423721 is a wasteful number, since it uses less digits than its factorization.

105423721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2332 (or 2319 counting only the distinct ones).

The product of its (nonzero) digits is 1680, while the sum is 25.

The square root of 105423721 is about 10267.6054170386. The cubic root of 105423721 is about 472.4031450460.

The spelling of 105423721 in words is "one hundred five million, four hundred twenty-three thousand, seven hundred twenty-one".