20001021021077 has 2 divisors, whose sum is σ = 20001021021078. Its totient is φ = 20001021021076.

The previous prime is 20001021020993. The next prime is 20001021021103. The reversal of 20001021021077 is 77012012010002.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10107064663921 + 9893956357156 = 3179161^2 + 3145466^2 .

It is a cyclic number.

It is not a de Polignac number, because 20001021021077 - 2⁸ = 20001021020821 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20001021021577) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10000510510538 + 10000510510539.

It is an arithmetic number, because the mean of its divisors is an integer number (10000510510539).

Almost surely, 2^{20001021021077} is an apocalyptic number.

It is an amenable number.

20001021021077 is a deficient number, since it is larger than the sum of its proper divisors (1).

20001021021077 is an equidigital number, since it uses as much as digits as its factorization.

20001021021077 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 392, while the sum is 23.

Adding to 20001021021077 its reverse (77012012010002), we get a palindrome (97013033031079).

The spelling of 20001021021077 in words is "twenty trillion, one billion, twenty-one million, twenty-one thousand, seventy-seven".