21906837727 has 2 divisors, whose sum is σ = 21906837728. Its totient is φ = 21906837726.

The previous prime is 21906837703. The next prime is 21906837737. The reversal of 21906837727 is 72773860912.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21906837727 - 2¹¹ = 21906835679 is a prime.

It is a super-2 number, since 2×21906837727² (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 (21906837737) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10953418863 + 10953418864.

It is an arithmetic number, because the mean of its divisors is an integer number (10953418864).

Almost surely, 2^21906837727 is an apocalyptic number.

21906837727 is a deficient number, since it is larger than the sum of its proper divisors (1).

21906837727 is an equidigital number, since it uses as much as digits as its factorization.

21906837727 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1778112, while the sum is 52.

The spelling of 21906837727 in words is "twenty-one billion, nine hundred six million, eight hundred thirty-seven thousand, seven hundred twenty-seven".