21489364069 has 2 divisors, whose sum is σ = 21489364070. Its totient is φ = 21489364068.

The previous prime is 21489364049. The next prime is 21489364073. The reversal of 21489364069 is 96046398412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13096055844 + 8393308225 = 114438^2 + 91615^2 .

It is a cyclic number.

It is not a de Polignac number, because 21489364069 - 2¹⁵ = 21489331301 is a prime.

It is a super-2 number, since 2×21489364069² (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 (21489364049) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10744682034 + 10744682035.

It is an arithmetic number, because the mean of its divisors is an integer number (10744682035).

Almost surely, 2^21489364069 is an apocalyptic number.

It is an amenable number.

21489364069 is a deficient number, since it is larger than the sum of its proper divisors (1).

21489364069 is an equidigital number, since it uses as much as digits as its factorization.

21489364069 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2239488, while the sum is 52.

The spelling of 21489364069 in words is "twenty-one billion, four hundred eighty-nine million, three hundred sixty-four thousand, sixty-nine".