21142120361 has 2 divisors, whose sum is σ = 21142120362. Its totient is φ = 21142120360.

The previous prime is 21142120339. The next prime is 21142120387. The reversal of 21142120361 is 16302124112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13506855961 + 7635264400 = 116219^2 + 87380^2 .

It is a cyclic number.

It is not a de Polignac number, because 21142120361 - 2²⁶ = 21075011497 is a prime.

It is not a weakly prime, because it can be changed into another prime (21142120061) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10571060180 + 10571060181.

It is an arithmetic number, because the mean of its divisors is an integer number (10571060181).

Almost surely, 2^21142120361 is an apocalyptic number.

It is an amenable number.

21142120361 is a deficient number, since it is larger than the sum of its proper divisors (1).

21142120361 is an equidigital number, since it uses as much as digits as its factorization.

21142120361 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 576, while the sum is 23.

Adding to 21142120361 its reverse (16302124112), we get a palindrome (37444244473).

The spelling of 21142120361 in words is "twenty-one billion, one hundred forty-two million, one hundred twenty thousand, three hundred sixty-one".