891151859344421 has 2 divisors, whose sum is σ = 891151859344422. Its totient is φ = 891151859344420.

The previous prime is 891151859344297. The next prime is 891151859344457. The reversal of 891151859344421 is 124443958151198.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 646232833632100 + 244919025712321 = 25421110^2 + 15649889^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-891151859344421 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (891151859344921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 445575929672210 + 445575929672211.

It is an arithmetic number, because the mean of its divisors is an integer number (445575929672211).

Almost surely, 2^{891151859344421} is an apocalyptic number.

It is an amenable number.

891151859344421 is a deficient number, since it is larger than the sum of its proper divisors (1).

891151859344421 is an equidigital number, since it uses as much as digits as its factorization.

891151859344421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 49766400, while the sum is 65.

The spelling of 891151859344421 in words is "eight hundred ninety-one trillion, one hundred fifty-one billion, eight hundred fifty-nine million, three hundred forty-four thousand, four hundred twenty-one".