1721099797 has 4 divisors (see below), whose sum is σ = 1750271040. Its totient is φ = 1691928556.

The previous prime is 1721099791. The next prime is 1721099803. The reversal of 1721099797 is 7979901271.

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: 7979901271 = 29863 ⋅267217.

It is an interprime number because it is at equal distance from previous prime (1721099791) and next prime (1721099803).

It is a cyclic number.

It is not a de Polignac number, because 1721099797 - 2³ = 1721099789 is a prime.

It is a super-2 number, since 2×1721099797² = 5924369022466882418, 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 (1721099791) 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, 14585533 + ... + 14585650.

It is an arithmetic number, because the mean of its divisors is an integer number (437567760).

Almost surely, 2^1721099797 is an apocalyptic number.

It is an amenable number.

1721099797 is a deficient number, since it is larger than the sum of its proper divisors (29171243).

1721099797 is an equidigital number, since it uses as much as digits as its factorization.

1721099797 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29171242.

The product of its (nonzero) digits is 500094, while the sum is 52.

The square root of 1721099797 is about 41486.1398180163. The cubic root of 1721099797 is about 1198.4006000005.

The spelling of 1721099797 in words is "one billion, seven hundred twenty-one million, ninety-nine thousand, seven hundred ninety-seven".