21274063781 has 2 divisors, whose sum is σ = 21274063782. Its totient is φ = 21274063780.

The previous prime is 21274063729. The next prime is 21274063793. The reversal of 21274063781 is 18736047212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18937888225 + 2336175556 = 137615^2 + 48334^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21274063781 is a prime.

It is a super-2 number, since 2×21274063781² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21274069781) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10637031890 + 10637031891.

It is an arithmetic number, because the mean of its divisors is an integer number (10637031891).

Almost surely, 2^21274063781 is an apocalyptic number.

It is an amenable number.

21274063781 is a deficient number, since it is larger than the sum of its proper divisors (1).

21274063781 is an equidigital number, since it uses as much as digits as its factorization.

21274063781 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 112896, while the sum is 41.

The spelling of 21274063781 in words is "twenty-one billion, two hundred seventy-four million, sixty-three thousand, seven hundred eighty-one".