21011357 has 2 divisors, whose sum is σ = 21011358. Its totient is φ = 21011356.

The previous prime is 21011327. The next prime is 21011383. The reversal of 21011357 is 75311012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13498276 + 7513081 = 3674^2 + 2741^2 .

It is a cyclic number.

It is not a de Polignac number, because 21011357 - 2⁶ = 21011293 is a prime.

It is a Chen prime.

It is equal to p_1330643 and since 21011357 and 1330643 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21011317) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10505678 + 10505679.

It is an arithmetic number, because the mean of its divisors is an integer number (10505679).

Almost surely, 2^21011357 is an apocalyptic number.

It is an amenable number.

21011357 is a deficient number, since it is larger than the sum of its proper divisors (1).

21011357 is an equidigital number, since it uses as much as digits as its factorization.

21011357 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 210, while the sum is 20.

The square root of 21011357 is about 4583.8146777548. The cubic root of 21011357 is about 275.9421437574.

Adding to 21011357 its reverse (75311012), we get a palindrome (96322369).

The spelling of 21011357 in words is "twenty-one million, eleven thousand, three hundred fifty-seven".