20129453557 has 2 divisors, whose sum is σ = 20129453558. Its totient is φ = 20129453556.

The previous prime is 20129453543. The next prime is 20129453569. The reversal of 20129453557 is 75535492102.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16587894436 + 3541559121 = 128794^2 + 59511^2 .

It is a cyclic number.

It is not a de Polignac number, because 20129453557 - 2¹⁵ = 20129420789 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20129453507) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10064726778 + 10064726779.

It is an arithmetic number, because the mean of its divisors is an integer number (10064726779).

Almost surely, 2^20129453557 is an apocalyptic number.

It is an amenable number.

20129453557 is a deficient number, since it is larger than the sum of its proper divisors (1).

20129453557 is an equidigital number, since it uses as much as digits as its factorization.

20129453557 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 378000, while the sum is 43.

The spelling of 20129453557 in words is "twenty billion, one hundred twenty-nine million, four hundred fifty-three thousand, five hundred fifty-seven".