21131069 has 2 divisors, whose sum is σ = 21131070. Its totient is φ = 21131068.

The previous prime is 21131041. The next prime is 21131081. The reversal of 21131069 is 96013112.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20811844 + 319225 = 4562^2 + 565^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21131069 is a prime.

It is a super-2 number, since 2×21131069² = 893044154165522, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21131009) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10565534 + 10565535.

It is an arithmetic number, because the mean of its divisors is an integer number (10565535).

Almost surely, 2^21131069 is an apocalyptic number.

It is an amenable number.

21131069 is a deficient number, since it is larger than the sum of its proper divisors (1).

21131069 is an equidigital number, since it uses as much as digits as its factorization.

21131069 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 324, while the sum is 23.

The square root of 21131069 is about 4596.8542504630. The cubic root of 21131069 is about 276.4652108391.

The spelling of 21131069 in words is "twenty-one million, one hundred thirty-one thousand, sixty-nine".