21650241553 has 4 divisors (see below), whose sum is σ = 21651160500. Its totient is φ = 21649322608.

The previous prime is 21650241551. The next prime is 21650241601. The reversal of 21650241553 is 35514205612.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 5196535569 + 16453705984 = 72087^2 + 128272^2 .

It is a cyclic number.

It is not a de Polignac number, because 21650241553 - 2¹ = 21650241551 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21650241551) 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, 423178 + ... + 471571.

It is an arithmetic number, because the mean of its divisors is an integer number (5412790125).

Almost surely, 2^21650241553 is an apocalyptic number.

It is an amenable number.

21650241553 is a deficient number, since it is larger than the sum of its proper divisors (918947).

21650241553 is an equidigital number, since it uses as much as digits as its factorization.

21650241553 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 918946.

The product of its (nonzero) digits is 36000, while the sum is 34.

The spelling of 21650241553 in words is "twenty-one billion, six hundred fifty million, two hundred forty-one thousand, five hundred fifty-three".