97781791 has 2 divisors, whose sum is σ = 97781792. Its totient is φ = 97781790.

The previous prime is 97781779. The next prime is 97781833. The reversal of 97781791 is 19718779.

It is a weak prime.

It is an emirp because it is prime and its reverse (19718779) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 97781791 - 2⁵ = 97781759 is a prime.

It is a super-2 number, since 2×97781791² = 19122557302335362, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (97781701) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 48890895 + 48890896.

It is an arithmetic number, because the mean of its divisors is an integer number (48890896).

Almost surely, 2^97781791 is an apocalyptic number.

97781791 is a deficient number, since it is larger than the sum of its proper divisors (1).

97781791 is an equidigital number, since it uses as much as digits as its factorization.

97781791 is an evil number, because the sum of its binary digits is even.

The product of its digits is 222264, while the sum is 49.

The square root of 97781791 is about 9888.4675759189. The cubic root of 97781791 is about 460.7011848836.

The spelling of 97781791 in words is "ninety-seven million, seven hundred eighty-one thousand, seven hundred ninety-one".