21550274461 has 4 divisors (see below), whose sum is σ = 21550570524. Its totient is φ = 21549978400.

The previous prime is 21550274443. The next prime is 21550274467. The reversal of 21550274461 is 16447205512.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 16691348025 + 4858926436 = 129195^2 + 69706^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21550274461 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21550274461.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21550274467) 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, 45441 + ... + 212521.

It is an arithmetic number, because the mean of its divisors is an integer number (5387642631).

Almost surely, 2^21550274461 is an apocalyptic number.

It is an amenable number.

21550274461 is a deficient number, since it is larger than the sum of its proper divisors (296063).

21550274461 is a wasteful number, since it uses less digits than its factorization.

21550274461 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 296062.

The product of its (nonzero) digits is 67200, while the sum is 37.

Adding to 21550274461 its reverse (16447205512), we get a palindrome (37997479973).

The spelling of 21550274461 in words is "twenty-one billion, five hundred fifty million, two hundred seventy-four thousand, four hundred sixty-one".