20154311521 has 2 divisors, whose sum is σ = 20154311522. Its totient is φ = 20154311520.

The previous prime is 20154311497. The next prime is 20154311549. The reversal of 20154311521 is 12511345102.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18860902225 + 1293409296 = 137335^2 + 35964^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20154311521 is a prime.

It is not a weakly prime, because it can be changed into another prime (20154311561) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10077155760 + 10077155761.

It is an arithmetic number, because the mean of its divisors is an integer number (10077155761).

Almost surely, 2^20154311521 is an apocalyptic number.

It is an amenable number.

20154311521 is a deficient number, since it is larger than the sum of its proper divisors (1).

20154311521 is an equidigital number, since it uses as much as digits as its factorization.

20154311521 is an odious number, because the sum of its binary digits is odd.

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

Adding to 20154311521 its reverse (12511345102), we get a palindrome (32665656623).

The spelling of 20154311521 in words is "twenty billion, one hundred fifty-four million, three hundred eleven thousand, five hundred twenty-one".