21647413 has 2 divisors, whose sum is σ = 21647414. Its totient is φ = 21647412.

The previous prime is 21647411. The next prime is 21647429. The reversal of 21647413 is 31474612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21325924 + 321489 = 4618^2 + 567^2 .

It is a cyclic number.

It is not a de Polignac number, because 21647413 - 2¹ = 21647411 is a prime.

It is a super-2 number, since 2×21647413² = 937220979185138, which contains 22 as substring.

Together with 21647411, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21647411) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10823706 + 10823707.

It is an arithmetic number, because the mean of its divisors is an integer number (10823707).

Almost surely, 2^21647413 is an apocalyptic number.

It is an amenable number.

21647413 is a deficient number, since it is larger than the sum of its proper divisors (1).

21647413 is an equidigital number, since it uses as much as digits as its factorization.

21647413 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4032, while the sum is 28.

The square root of 21647413 is about 4652.6780460290. The cubic root of 21647413 is about 278.6989511510.

The spelling of 21647413 in words is "twenty-one million, six hundred forty-seven thousand, four hundred thirteen".