21256020030653 has 4 divisors (see below), whose sum is σ = 21256029253248. Its totient is φ = 21256010808060.

The previous prime is 21256020030649. The next prime is 21256020030673. The reversal of 21256020030653 is 35603002065212.

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, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21256020030653 - 2² = 21256020030649 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21256020030673) 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, 2171150 + ... + 6872112.

It is an arithmetic number, because the mean of its divisors is an integer number (5314007313312).

Almost surely, 2^{21256020030653} is an apocalyptic number.

It is an amenable number.

21256020030653 is a deficient number, since it is larger than the sum of its proper divisors (9222595).

21256020030653 is an equidigital number, since it uses as much as digits as its factorization.

21256020030653 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9222594.

The product of its (nonzero) digits is 64800, while the sum is 35.

Adding to 21256020030653 its reverse (35603002065212), we get a palindrome (56859022095865).

The spelling of 21256020030653 in words is "twenty-one trillion, two hundred fifty-six billion, twenty million, thirty thousand, six hundred fifty-three".