20195013752561 has 2 divisors, whose sum is σ = 20195013752562. Its totient is φ = 20195013752560.

The previous prime is 20195013752549. The next prime is 20195013752663. The reversal of 20195013752561 is 16525731059102.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13346162497600 + 6848851254961 = 3653240^2 + 2617031^2 .

It is a cyclic number.

It is not a de Polignac number, because 20195013752561 - 2¹⁰ = 20195013751537 is a prime.

It is a super-2 number, since 2×20195013752561² (a number of 27 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (20195013752261) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10097506876280 + 10097506876281.

It is an arithmetic number, because the mean of its divisors is an integer number (10097506876281).

Almost surely, 2^{20195013752561} is an apocalyptic number.

It is an amenable number.

20195013752561 is a deficient number, since it is larger than the sum of its proper divisors (1).

20195013752561 is an equidigital number, since it uses as much as digits as its factorization.

20195013752561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 567000, while the sum is 47.

The spelling of 20195013752561 in words is "twenty trillion, one hundred ninety-five billion, thirteen million, seven hundred fifty-two thousand, five hundred sixty-one".