19912961 has 2 divisors, whose sum is σ = 19912962. Its totient is φ = 19912960.

The previous prime is 19912951. The next prime is 19912979. The reversal of 19912961 is 16921991.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17272336 + 2640625 = 4156^2 + 1625^2 .

It is a cyclic number.

It is not a de Polignac number, because 19912961 - 2¹⁴ = 19896577 is a prime.

It is not a weakly prime, because it can be changed into another prime (19912951) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9956480 + 9956481.

It is an arithmetic number, because the mean of its divisors is an integer number (9956481).

Almost surely, 2^19912961 is an apocalyptic number.

It is an amenable number.

19912961 is a deficient number, since it is larger than the sum of its proper divisors (1).

19912961 is an equidigital number, since it uses as much as digits as its factorization.

19912961 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8748, while the sum is 38.

The square root of 19912961 is about 4462.3940883790. The cubic root of 19912961 is about 271.0474220648.

The spelling of 19912961 in words is "nineteen million, nine hundred twelve thousand, nine hundred sixty-one".