191720069 has 4 divisors (see below), whose sum is σ = 191758560. Its totient is φ = 191681580.

The previous prime is 191720063. The next prime is 191720071. The reversal of 191720069 is 960027191.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 960027191 = 1013 ⋅947707.

It is a cyclic number.

It is not a de Polignac number, because 191720069 - 2²⁰ = 190671493 is a prime.

It is a super-2 number, since 2×191720069² = 73513169714729522, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (191720063) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10427 + ... + 22184.

It is an arithmetic number, because the mean of its divisors is an integer number (47939640).

Almost surely, 2^191720069 is an apocalyptic number.

It is an amenable number.

191720069 is a deficient number, since it is larger than the sum of its proper divisors (38491).

191720069 is an equidigital number, since it uses as much as digits as its factorization.

191720069 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38490.

The product of its (nonzero) digits is 6804, while the sum is 35.

The square root of 191720069 is about 13846.3016361771. The cubic root of 191720069 is about 576.6193234473.

The spelling of 191720069 in words is "one hundred ninety-one million, seven hundred twenty thousand, sixty-nine".