20211220061 has 2 divisors, whose sum is σ = 20211220062. Its totient is φ = 20211220060.

The previous prime is 20211220013. The next prime is 20211220063. The reversal of 20211220061 is 16002211202.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14572111225 + 5639108836 = 120715^2 + 75094^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20211220061 is a prime.

Together with 20211220063, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20211220063) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10105610030 + 10105610031.

It is an arithmetic number, because the mean of its divisors is an integer number (10105610031).

Almost surely, 2^20211220061 is an apocalyptic number.

It is an amenable number.

20211220061 is a deficient number, since it is larger than the sum of its proper divisors (1).

20211220061 is an equidigital number, since it uses as much as digits as its factorization.

20211220061 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 96, while the sum is 17.

Adding to 20211220061 its reverse (16002211202), we get a palindrome (36213431263).

The spelling of 20211220061 in words is "twenty billion, two hundred eleven million, two hundred twenty thousand, sixty-one".