1699421609 has 4 divisors (see below), whose sum is σ = 1799387604. Its totient is φ = 1599455616.

The previous prime is 1699421599. The next prime is 1699421621. The reversal of 1699421609 is 9061249961.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9061249961 = 1619 ⋅5596819.

It can be written as a sum of positive squares in 2 ways, for example, as 695482384 + 1003939225 = 26372^2 + 31685^2 .

It is a cyclic number.

It is not a de Polignac number, because 1699421609 - 2²⁸ = 1430986153 is a prime.

It is a super-2 number, since 2×1699421609² = 5776067610272297762, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1699421639) 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, 49982972 + ... + 49983005.

It is an arithmetic number, because the mean of its divisors is an integer number (449846901).

Almost surely, 2^1699421609 is an apocalyptic number.

It is an amenable number.

1699421609 is a deficient number, since it is larger than the sum of its proper divisors (99965995).

1699421609 is an equidigital number, since it uses as much as digits as its factorization.

1699421609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 99965994.

The product of its (nonzero) digits is 209952, while the sum is 47.

The square root of 1699421609 is about 41224.0416383450. The cubic root of 1699421609 is about 1193.3478236453.

The spelling of 1699421609 in words is "one billion, six hundred ninety-nine million, four hundred twenty-one thousand, six hundred nine".