21203503970581 has 4 divisors (see below), whose sum is σ = 21887487969664. Its totient is φ = 20519519971500.

The previous prime is 21203503970533. The next prime is 21203503970641. The reversal of 21203503970581 is 18507930530212.

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 a cyclic number.

It is not a de Polignac number, because 21203503970581 - 2²⁹ = 21202967099669 is a prime.

It is a super-2 number, since 2×21203503970581² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21203513970581) 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, 341991999495 + ... + 341991999556.

It is an arithmetic number, because the mean of its divisors is an integer number (5471871992416).

Almost surely, 2^{21203503970581} is an apocalyptic number.

It is an amenable number.

21203503970581 is a deficient number, since it is larger than the sum of its proper divisors (683983999083).

21203503970581 is an equidigital number, since it uses as much as digits as its factorization.

21203503970581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 683983999082.

The product of its (nonzero) digits is 453600, while the sum is 46.

The spelling of 21203503970581 in words is "twenty-one trillion, two hundred three billion, five hundred three million, nine hundred seventy thousand, five hundred eighty-one".