21656021119 has 2 divisors, whose sum is σ = 21656021120. Its totient is φ = 21656021118.

The previous prime is 21656021099. The next prime is 21656021143. The reversal of 21656021119 is 91112065612.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21656021119 - 2⁵ = 21656021087 is a prime.

It is a super-2 number, since 2×21656021119² (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 (21656021159) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10828010559 + 10828010560.

It is an arithmetic number, because the mean of its divisors is an integer number (10828010560).

Almost surely, 2^21656021119 is an apocalyptic number.

21656021119 is a deficient number, since it is larger than the sum of its proper divisors (1).

21656021119 is an equidigital number, since it uses as much as digits as its factorization.

21656021119 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6480, while the sum is 34.

The spelling of 21656021119 in words is "twenty-one billion, six hundred fifty-six million, twenty-one thousand, one hundred nineteen".