21520523212521 has 8 divisors (see below), whose sum is σ = 28697036542944. Its totient is φ = 14345512678560.

The previous prime is 21520523212423. The next prime is 21520523212543. The reversal of 21520523212521 is 12521232502512.

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

It is not a de Polignac number, because 21520523212521 - 2³³ = 21511933277929 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21520523212571) 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, 375665700 + ... + 375722981.

It is an arithmetic number, because the mean of its divisors is an integer number (3587129567868).

Almost surely, 2^{21520523212521} is an apocalyptic number.

It is an amenable number.

21520523212521 is a deficient number, since it is larger than the sum of its proper divisors (7176513330423).

21520523212521 is an equidigital number, since it uses as much as digits as its factorization.

21520523212521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 751398231.

The product of its (nonzero) digits is 24000, while the sum is 33.

The spelling of 21520523212521 in words is "twenty-one trillion, five hundred twenty billion, five hundred twenty-three million, two hundred twelve thousand, five hundred twenty-one".