21429877771 has 2 divisors, whose sum is σ = 21429877772. Its totient is φ = 21429877770.

The previous prime is 21429877669. The next prime is 21429877877. The reversal of 21429877771 is 17777892412.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21429877771 - 2¹¹ = 21429875723 is a prime.

It is a super-2 number, since 2×21429877771² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21429877571) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10714938885 + 10714938886.

It is an arithmetic number, because the mean of its divisors is an integer number (10714938886).

Almost surely, 2^21429877771 is an apocalyptic number.

21429877771 is a deficient number, since it is larger than the sum of its proper divisors (1).

21429877771 is an equidigital number, since it uses as much as digits as its factorization.

21429877771 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2765952, while the sum is 55.

The spelling of 21429877771 in words is "twenty-one billion, four hundred twenty-nine million, eight hundred seventy-seven thousand, seven hundred seventy-one".