21239470237521 has 4 divisors (see below), whose sum is σ = 28319293650032. Its totient is φ = 14159646825012.

The previous prime is 21239470237511. The next prime is 21239470237523. The reversal of 21239470237521 is 12573207493212.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 21239470237521 - 2¹⁰ = 21239470236497 is a prime.

It is a super-2 number, since 2×21239470237521² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21239470237523) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3539911706251 + ... + 3539911706256.

It is an arithmetic number, because the mean of its divisors is an integer number (7079823412508).

Almost surely, 2^{21239470237521} is an apocalyptic number.

It is an amenable number.

21239470237521 is a deficient number, since it is larger than the sum of its proper divisors (7079823412511).

21239470237521 is an equidigital number, since it uses as much as digits as its factorization.

21239470237521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7079823412510.

The product of its (nonzero) digits is 1270080, while the sum is 48.

The spelling of 21239470237521 in words is "twenty-one trillion, two hundred thirty-nine billion, four hundred seventy million, two hundred thirty-seven thousand, five hundred twenty-one".