21358501 has 2 divisors, whose sum is σ = 21358502. Its totient is φ = 21358500.

The previous prime is 21358457. The next prime is 21358537. The reversal of 21358501 is 10585312.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20205025 + 1153476 = 4495^2 + 1074^2 .

It is a cyclic number.

It is not a de Polignac number, because 21358501 - 2⁷ = 21358373 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21358201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10679250 + 10679251.

It is an arithmetic number, because the mean of its divisors is an integer number (10679251).

Almost surely, 2^21358501 is an apocalyptic number.

It is an amenable number.

21358501 is a deficient number, since it is larger than the sum of its proper divisors (1).

21358501 is an equidigital number, since it uses as much as digits as its factorization.

21358501 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1200, while the sum is 25.

The square root of 21358501 is about 4621.5258302859. The cubic root of 21358501 is about 277.4535311633.

The spelling of 21358501 in words is "twenty-one million, three hundred fifty-eight thousand, five hundred one".