20919076261 has 2 divisors, whose sum is σ = 20919076262. Its totient is φ = 20919076260.

The previous prime is 20919076259. The next prime is 20919076313. The reversal of 20919076261 is 16267091902.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19236025636 + 1683050625 = 138694^2 + 41025^2 .

It is a cyclic number.

It is not a de Polignac number, because 20919076261 - 2¹ = 20919076259 is a prime.

It is a super-2 number, since 2×20919076261² (a number of 21 digits) contains 22 as substring.

Together with 20919076259, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20919076201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10459538130 + 10459538131.

It is an arithmetic number, because the mean of its divisors is an integer number (10459538131).

Almost surely, 2^20919076261 is an apocalyptic number.

It is an amenable number.

20919076261 is a deficient number, since it is larger than the sum of its proper divisors (1).

20919076261 is an equidigital number, since it uses as much as digits as its factorization.

20919076261 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 81648, while the sum is 43.

The spelling of 20919076261 in words is "twenty billion, nine hundred nineteen million, seventy-six thousand, two hundred sixty-one".