21105655429 has 2 divisors, whose sum is σ = 21105655430. Its totient is φ = 21105655428.

The previous prime is 21105655421. The next prime is 21105655451. The reversal of 21105655429 is 92455650112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12344321025 + 8761334404 = 111105^2 + 93602^2 .

It is a cyclic number.

It is not a de Polignac number, because 21105655429 - 2³ = 21105655421 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21105655391 and 21105655400.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21105655421) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10552827714 + 10552827715.

It is an arithmetic number, because the mean of its divisors is an integer number (10552827715).

Almost surely, 2^21105655429 is an apocalyptic number.

It is an amenable number.

21105655429 is a deficient number, since it is larger than the sum of its proper divisors (1).

21105655429 is an equidigital number, since it uses as much as digits as its factorization.

21105655429 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 108000, while the sum is 40.

The spelling of 21105655429 in words is "twenty-one billion, one hundred five million, six hundred fifty-five thousand, four hundred twenty-nine".