20237521 has 2 divisors, whose sum is σ = 20237522. Its totient is φ = 20237520.

The previous prime is 20237507. The next prime is 20237533. The reversal of 20237521 is 12573202.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13140625 + 7096896 = 3625^2 + 2664^2 .

It is a cyclic number.

It is not a de Polignac number, because 20237521 - 2¹¹ = 20235473 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 20237492 and 20237501.

It is not a weakly prime, because it can be changed into another prime (20237501) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10118760 + 10118761.

It is an arithmetic number, because the mean of its divisors is an integer number (10118761).

Almost surely, 2^20237521 is an apocalyptic number.

It is an amenable number.

20237521 is a deficient number, since it is larger than the sum of its proper divisors (1).

20237521 is an equidigital number, since it uses as much as digits as its factorization.

20237521 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 840, while the sum is 22.

The square root of 20237521 is about 4498.6132307635. The cubic root of 20237521 is about 272.5120876719.

The spelling of 20237521 in words is "twenty million, two hundred thirty-seven thousand, five hundred twenty-one".