2191477621 has 2 divisors, whose sum is σ = 2191477622. Its totient is φ = 2191477620.

The previous prime is 2191477609. The next prime is 2191477627. The reversal of 2191477621 is 1267741912.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1502415121 + 689062500 = 38761^2 + 26250^2 .

It is a cyclic number.

It is not a de Polignac number, because 2191477621 - 2⁷ = 2191477493 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2191477627) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1095738810 + 1095738811.

It is an arithmetic number, because the mean of its divisors is an integer number (1095738811).

Almost surely, 2^2191477621 is an apocalyptic number.

It is an amenable number.

2191477621 is a deficient number, since it is larger than the sum of its proper divisors (1).

2191477621 is an equidigital number, since it uses as much as digits as its factorization.

2191477621 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 42336, while the sum is 40.

The square root of 2191477621 is about 46813.2205792338. The cubic root of 2191477621 is about 1298.9098594696.

The spelling of 2191477621 in words is "two billion, one hundred ninety-one million, four hundred seventy-seven thousand, six hundred twenty-one".