21371769 has 10 divisors (see below), whose sum is σ = 31925850. Its totient is φ = 14247792.

The previous prime is 21371767. The next prime is 21371797. The reversal of 21371769 is 96717312.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 15896169 + 5475600 = 3987^2 + 2340^2 .

It is not a de Polignac number, because 21371769 - 2¹ = 21371767 is a prime.

It is a super-2 number, since 2×21371769² = 913505020378722, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21371767) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 131844 + ... + 132005.

It is an arithmetic number, because the mean of its divisors is an integer number (3192585).

Almost surely, 2^21371769 is an apocalyptic number.

It is an amenable number.

21371769 is a deficient number, since it is larger than the sum of its proper divisors (10554081).

21371769 is an equidigital number, since it uses as much as digits as its factorization.

21371769 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 263861 (or 263852 counting only the distinct ones).

The product of its digits is 15876, while the sum is 36.

The square root of 21371769 is about 4622.9610640800. The cubic root of 21371769 is about 277.5109710783.

The spelling of 21371769 in words is "twenty-one million, three hundred seventy-one thousand, seven hundred sixty-nine".