213921649757 has 2 divisors, whose sum is σ = 213921649758. Its totient is φ = 213921649756.

The previous prime is 213921649699. The next prime is 213921649789. The reversal of 213921649757 is 757946129312.

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., 177825829636 + 36095820121 = 421694^2 + 189989^2 .

It is a cyclic number.

It is not a de Polignac number, because 213921649757 - 2²⁴ = 213904872541 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (213921649057) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106960824878 + 106960824879.

It is an arithmetic number, because the mean of its divisors is an integer number (106960824879).

Almost surely, 2^213921649757 is an apocalyptic number.

It is an amenable number.

213921649757 is a deficient number, since it is larger than the sum of its proper divisors (1).

213921649757 is an equidigital number, since it uses as much as digits as its factorization.

213921649757 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5715360, while the sum is 56.

The spelling of 213921649757 in words is "two hundred thirteen billion, nine hundred twenty-one million, six hundred forty-nine thousand, seven hundred fifty-seven".