21012373 has 2 divisors, whose sum is σ = 21012374. Its totient is φ = 21012372.

The previous prime is 21012371. The next prime is 21012401. The reversal of 21012373 is 37321012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20958084 + 54289 = 4578^2 + 233^2 .

It is a cyclic number.

It is not a de Polignac number, because 21012373 - 2¹ = 21012371 is a prime.

It is a super-2 number, since 2×21012373² = 883039638182258, which contains 22 as substring.

Together with 21012371, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 21012373.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21012371) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10506186 + 10506187.

It is an arithmetic number, because the mean of its divisors is an integer number (10506187).

Almost surely, 2^21012373 is an apocalyptic number.

It is an amenable number.

21012373 is a deficient number, since it is larger than the sum of its proper divisors (1).

21012373 is an equidigital number, since it uses as much as digits as its factorization.

21012373 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 252, while the sum is 19.

The square root of 21012373 is about 4583.9255011398. The cubic root of 21012373 is about 275.9465913949.

Adding to 21012373 its reverse (37321012), we get a palindrome (58333385).

The spelling of 21012373 in words is "twenty-one million, twelve thousand, three hundred seventy-three".