191016421 has 2 divisors, whose sum is σ = 191016422. Its totient is φ = 191016420.

The previous prime is 191016409. The next prime is 191016467. The reversal of 191016421 is 124610191.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 185776900 + 5239521 = 13630^2 + 2289^2 .

It is a cyclic number.

It is not a de Polignac number, because 191016421 - 2²³ = 182627813 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (191016491) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 95508210 + 95508211.

It is an arithmetic number, because the mean of its divisors is an integer number (95508211).

Almost surely, 2^191016421 is an apocalyptic number.

It is an amenable number.

191016421 is a deficient number, since it is larger than the sum of its proper divisors (1).

191016421 is an equidigital number, since it uses as much as digits as its factorization.

191016421 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 432, while the sum is 25.

The square root of 191016421 is about 13820.8690392464. The cubic root of 191016421 is about 575.9130255846.

The spelling of 191016421 in words is "one hundred ninety-one million, sixteen thousand, four hundred twenty-one".