101421721 has 4 divisors (see below), whose sum is σ = 101982244. Its totient is φ = 100861200.

The previous prime is 101421713. The next prime is 101421751. The reversal of 101421721 is 127124101.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 33177600 + 68244121 = 5760^2 + 8261^2 .

It is a cyclic number.

It is not a de Polignac number, because 101421721 - 2³ = 101421713 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (101421751) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 279990 + ... + 280351.

It is an arithmetic number, because the mean of its divisors is an integer number (25495561).

Almost surely, 2^101421721 is an apocalyptic number.

It is an amenable number.

101421721 is a deficient number, since it is larger than the sum of its proper divisors (560523).

101421721 is an equidigital number, since it uses as much as digits as its factorization.

101421721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 560522.

The product of its (nonzero) digits is 112, while the sum is 19.

The square root of 101421721 is about 10070.8351689420. The cubic root of 101421721 is about 466.3482219209.

Adding to 101421721 its reverse (127124101), we get a palindrome (228545822).

The spelling of 101421721 in words is "one hundred one million, four hundred twenty-one thousand, seven hundred twenty-one".