21170641 has 2 divisors, whose sum is σ = 21170642. Its totient is φ = 21170640.

The previous prime is 21170629. The next prime is 21170647. The reversal of 21170641 is 14607112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17640000 + 3530641 = 4200^2 + 1879^2 .

It is a cyclic number.

It is not a de Polignac number, because 21170641 - 2¹¹ = 21168593 is a prime.

It is equal to p_1340059 and since 21170641 and 1340059 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (21170647) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10585320 + 10585321.

It is an arithmetic number, because the mean of its divisors is an integer number (10585321).

Almost surely, 2^21170641 is an apocalyptic number.

It is an amenable number.

21170641 is a deficient number, since it is larger than the sum of its proper divisors (1).

21170641 is an equidigital number, since it uses as much as digits as its factorization.

21170641 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 336, while the sum is 22.

The square root of 21170641 is about 4601.1564850589. The cubic root of 21170641 is about 276.6376813556.

Adding to 21170641 its reverse (14607112), we get a palindrome (35777753).

The spelling of 21170641 in words is "twenty-one million, one hundred seventy thousand, six hundred forty-one".