21477816697 has 2 divisors, whose sum is σ = 21477816698. Its totient is φ = 21477816696.

The previous prime is 21477816683. The next prime is 21477816719. The reversal of 21477816697 is 79661877412.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20126813161 + 1351003536 = 141869^2 + 36756^2 .

It is a cyclic number.

It is not a de Polignac number, because 21477816697 - 2²³ = 21469428089 is a prime.

It is a super-2 number, since 2×21477816697² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21477816637) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10738908348 + 10738908349.

It is an arithmetic number, because the mean of its divisors is an integer number (10738908349).

Almost surely, 2^21477816697 is an apocalyptic number.

It is an amenable number.

21477816697 is a deficient number, since it is larger than the sum of its proper divisors (1).

21477816697 is an equidigital number, since it uses as much as digits as its factorization.

21477816697 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7112448, while the sum is 58.

The spelling of 21477816697 in words is "twenty-one billion, four hundred seventy-seven million, eight hundred sixteen thousand, six hundred ninety-seven".