21765227461 has 6 divisors (see below), whose sum is σ = 21801983462. Its totient is φ = 21728533320.

The previous prime is 21765227443. The next prime is 21765227479. The reversal of 21765227461 is 16472256712.

It is an interprime number because it is at equal distance from previous prime (21765227443) and next prime (21765227479).

It can be written as a sum of positive squares in only one way, i.e., 15226079236 + 6539148225 = 123394^2 + 80865^2 .

It is not a de Polignac number, because 21765227461 - 2¹³ = 21765219269 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 (21765227161) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 328471 + ... + 389131.

Almost surely, 2^21765227461 is an apocalyptic number.

It is an amenable number.

21765227461 is a deficient number, since it is larger than the sum of its proper divisors (36756001).

21765227461 is an frugal number, since it uses more digits than its factorization.

21765227461 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 61859 (or 61260 counting only the distinct ones).

The product of its digits is 282240, while the sum is 43.

The spelling of 21765227461 in words is "twenty-one billion, seven hundred sixty-five million, two hundred twenty-seven thousand, four hundred sixty-one".