20499893521 has 2 divisors, whose sum is σ = 20499893522. Its totient is φ = 20499893520.

The previous prime is 20499893473. The next prime is 20499893563. The reversal of 20499893521 is 12539899402.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19554945921 + 944947600 = 139839^2 + 30740^2 .

It is a cyclic number.

It is not a de Polignac number, because 20499893521 - 2⁹ = 20499893009 is a prime.

It is not a weakly prime, because it can be changed into another prime (20499893221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10249946760 + 10249946761.

It is an arithmetic number, because the mean of its divisors is an integer number (10249946761).

Almost surely, 2^20499893521 is an apocalyptic number.

It is an amenable number.

20499893521 is a deficient number, since it is larger than the sum of its proper divisors (1).

20499893521 is an equidigital number, since it uses as much as digits as its factorization.

20499893521 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1399680, while the sum is 52.

The spelling of 20499893521 in words is "twenty billion, four hundred ninety-nine million, eight hundred ninety-three thousand, five hundred twenty-one".