101620861721 has 2 divisors, whose sum is σ = 101620861722. Its totient is φ = 101620861720.

The previous prime is 101620861709. The next prime is 101620861729. The reversal of 101620861721 is 127168026101.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 101585625625 + 35236096 = 318725^2 + 5936^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-101620861721 is a prime.

It is not a weakly prime, because it can be changed into another prime (101620861729) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 50810430860 + 50810430861.

It is an arithmetic number, because the mean of its divisors is an integer number (50810430861).

Almost surely, 2^101620861721 is an apocalyptic number.

It is an amenable number.

101620861721 is a deficient number, since it is larger than the sum of its proper divisors (1).

101620861721 is an equidigital number, since it uses as much as digits as its factorization.

101620861721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8064, while the sum is 35.

Adding to 101620861721 its reverse (127168026101), we get a palindrome (228788887822).

The spelling of 101620861721 in words is "one hundred one billion, six hundred twenty million, eight hundred sixty-one thousand, seven hundred twenty-one".