20521099 has 2 divisors, whose sum is σ = 20521100. Its totient is φ = 20521098.

The previous prime is 20521073. The next prime is 20521147. The reversal of 20521099 is 99012502.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20521099 - 2⁷ = 20520971 is a prime.

It is a super-2 number, since 2×20521099² = 842231008335602, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (20521049) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10260549 + 10260550.

It is an arithmetic number, because the mean of its divisors is an integer number (10260550).

Almost surely, 2^20521099 is an apocalyptic number.

20521099 is a deficient number, since it is larger than the sum of its proper divisors (1).

20521099 is an equidigital number, since it uses as much as digits as its factorization.

20521099 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1620, while the sum is 28.

The square root of 20521099 is about 4530.0219646267. The cubic root of 20521099 is about 273.7790455896.

The spelling of 20521099 in words is "twenty million, five hundred twenty-one thousand, ninety-nine".