101521721 has 8 divisors (see below), whose sum is σ = 120025920. Its totient is φ = 84017808.

The previous prime is 101521711. The next prime is 101521723. The reversal of 101521721 is 127125101.

It is a happy number.

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

It is not a de Polignac number, because 101521721 - 2¹⁴ = 101505337 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 101521693 and 101521702.

It is not an unprimeable number, because it can be changed into a prime (101521723) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 249851 + ... + 250256.

It is an arithmetic number, because the mean of its divisors is an integer number (15003240).

Almost surely, 2^101521721 is an apocalyptic number.

It is an amenable number.

101521721 is a deficient number, since it is larger than the sum of its proper divisors (18504199).

101521721 is an equidigital number, since it uses as much as digits as its factorization.

101521721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 500143.

The product of its (nonzero) digits is 140, while the sum is 20.

The square root of 101521721 is about 10075.7987772682. The cubic root of 101521721 is about 466.5014419054.

Adding to 101521721 its reverse (127125101), we get a palindrome (228646822).

The spelling of 101521721 in words is "one hundred one million, five hundred twenty-one thousand, seven hundred twenty-one".