19640149261 has 2 divisors, whose sum is σ = 19640149262. Its totient is φ = 19640149260.

The previous prime is 19640149237. The next prime is 19640149267. The reversal of 19640149261 is 16294104691.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10507480036 + 9132669225 = 102506^2 + 95565^2 .

It is a cyclic number.

It is not a de Polignac number, because 19640149261 - 2¹¹ = 19640147213 is a prime.

It is a super-2 number, since 2×19640149261² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19640149267) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9820074630 + 9820074631.

It is an arithmetic number, because the mean of its divisors is an integer number (9820074631).

Almost surely, 2^19640149261 is an apocalyptic number.

It is an amenable number.

19640149261 is a deficient number, since it is larger than the sum of its proper divisors (1).

19640149261 is an equidigital number, since it uses as much as digits as its factorization.

19640149261 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 93312, while the sum is 43.

The spelling of 19640149261 in words is "nineteen billion, six hundred forty million, one hundred forty-nine thousand, two hundred sixty-one".