21727236461 has 30 divisors (see below), whose sum is σ = 26859238470. Its totient is φ = 17524553088.

The previous prime is 21727236451. The next prime is 21727236463. The reversal of 21727236461 is 16463272712.

It can be written as a sum of positive squares in 5 ways, for example, as 588984361 + 21138252100 = 24269^2 + 145390^2 .

It is not a de Polignac number, because 21727236461 - 2²² = 21723042157 is a prime.

It is a super-3 number, since 3×21727236461³ (a number of 32 digits) contains 333 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 (21727236463) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 29 ways as a sum of consecutive naturals, for example, 4089875 + ... + 4095183.

It is an arithmetic number, because the mean of its divisors is an integer number (895307949).

Almost surely, 2^21727236461 is an apocalyptic number.

It is an amenable number.

21727236461 is a deficient number, since it is larger than the sum of its proper divisors (5132002009).

21727236461 is an frugal number, since it uses more digits than its factorization.

21727236461 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5391 (or 5333 counting only the distinct ones).

The product of its digits is 169344, while the sum is 41.

The spelling of 21727236461 in words is "twenty-one billion, seven hundred twenty-seven million, two hundred thirty-six thousand, four hundred sixty-one".