21050401 has 2 divisors, whose sum is σ = 21050402. Its totient is φ = 21050400.

The previous prime is 21050399. The next prime is 21050413. The reversal of 21050401 is 10405012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15023376 + 6027025 = 3876^2 + 2455^2 .

It is a cyclic number.

It is not a de Polignac number, because 21050401 - 2¹ = 21050399 is a prime.

Together with 21050399, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21050101) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10525200 + 10525201.

It is an arithmetic number, because the mean of its divisors is an integer number (10525201).

Almost surely, 2^21050401 is an apocalyptic number.

It is an amenable number.

21050401 is a deficient number, since it is larger than the sum of its proper divisors (1).

21050401 is an equidigital number, since it uses as much as digits as its factorization.

21050401 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 40, while the sum is 13.

The square root of 21050401 is about 4588.0715992670. The cubic root of 21050401 is about 276.1129596084.

Adding to 21050401 its reverse (10405012), we get a palindrome (31455413).

The spelling of 21050401 in words is "twenty-one million, fifty thousand, four hundred one".