213657470261 has 2 divisors, whose sum is σ = 213657470262. Its totient is φ = 213657470260.

The previous prime is 213657470239. The next prime is 213657470269. The reversal of 213657470261 is 162074756312.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 182683582225 + 30973888036 = 427415^2 + 175994^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-213657470261 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (213657470269) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106828735130 + 106828735131.

It is an arithmetic number, because the mean of its divisors is an integer number (106828735131).

Almost surely, 2^213657470261 is an apocalyptic number.

It is an amenable number.

213657470261 is a deficient number, since it is larger than the sum of its proper divisors (1).

213657470261 is an equidigital number, since it uses as much as digits as its factorization.

213657470261 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 423360, while the sum is 44.

The spelling of 213657470261 in words is "two hundred thirteen billion, six hundred fifty-seven million, four hundred seventy thousand, two hundred sixty-one".