1620698999 has 4 divisors (see below), whose sum is σ = 1621233600. Its totient is φ = 1620164400.

The previous prime is 1620698987. The next prime is 1620699007. The reversal of 1620698999 is 9998960261.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9998960261 = 17 ⋅588174133.

It is a cyclic number.

It is not a de Polignac number, because 1620698999 - 2¹⁶ = 1620633463 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1620698909) 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, 262727 + ... + 268824.

It is an arithmetic number, because the mean of its divisors is an integer number (405308400).

Almost surely, 2^1620698999 is an apocalyptic number.

1620698999 is a deficient number, since it is larger than the sum of its proper divisors (534601).

1620698999 is an equidigital number, since it uses as much as digits as its factorization.

1620698999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 534600.

The product of its (nonzero) digits is 3779136, while the sum is 59.

The square root of 1620698999 is about 40257.9060434097. The cubic root of 1620698999 is about 1174.6291871087.

The spelling of 1620698999 in words is "one billion, six hundred twenty million, six hundred ninety-eight thousand, nine hundred ninety-nine".