2158214850661 has 2 divisors, whose sum is σ = 2158214850662. Its totient is φ = 2158214850660.

The previous prime is 2158214850619. The next prime is 2158214850691. The reversal of 2158214850661 is 1660584128512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2151883624900 + 6331225761 = 1466930^2 + 79569^2 .

It is a cyclic number.

It is not a de Polignac number, because 2158214850661 - 2²³ = 2158206462053 is a prime.

It is a super-2 number, since 2×2158214850661² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2158214850691) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1079107425330 + 1079107425331.

It is an arithmetic number, because the mean of its divisors is an integer number (1079107425331).

Almost surely, 2^{2158214850661} is an apocalyptic number.

It is an amenable number.

2158214850661 is a deficient number, since it is larger than the sum of its proper divisors (1).

2158214850661 is an equidigital number, since it uses as much as digits as its factorization.

2158214850661 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 921600, while the sum is 49.

The spelling of 2158214850661 in words is "two trillion, one hundred fifty-eight billion, two hundred fourteen million, eight hundred fifty thousand, six hundred sixty-one".