20696521 has 2 divisors, whose sum is σ = 20696522. Its totient is φ = 20696520.

The previous prime is 20696503. The next prime is 20696549. The reversal of 20696521 is 12569602.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18020025 + 2676496 = 4245^2 + 1636^2 .

It is a cyclic number.

It is not a de Polignac number, because 20696521 - 2¹³ = 20688329 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (20696581) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10348260 + 10348261.

It is an arithmetic number, because the mean of its divisors is an integer number (10348261).

Almost surely, 2^20696521 is an apocalyptic number.

It is an amenable number.

20696521 is a deficient number, since it is larger than the sum of its proper divisors (1).

20696521 is an equidigital number, since it uses as much as digits as its factorization.

20696521 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6480, while the sum is 31.

The square root of 20696521 is about 4549.3429195874. The cubic root of 20696521 is about 274.5569549249.

The spelling of 20696521 in words is "twenty million, six hundred ninety-six thousand, five hundred twenty-one".