1620004991 has 6 divisors (see below), whose sum is σ = 1780666776. Its totient is φ = 1472731700.

The previous prime is 1620004957. The next prime is 1620005011. The reversal of 1620004991 is 1994000261.

It is not a de Polignac number, because 1620004991 - 2⁶ = 1620004927 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 (1620004901) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 6694115 + ... + 6694356.

It is an arithmetic number, because the mean of its divisors is an integer number (296777796).

Almost surely, 2^1620004991 is an apocalyptic number.

1620004991 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1620004991 is a deficient number, since it is larger than the sum of its proper divisors (160661785).

1620004991 is a wasteful number, since it uses less digits than its factorization.

1620004991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13388493 (or 13388482 counting only the distinct ones).

The product of its (nonzero) digits is 3888, while the sum is 32.

The square root of 1620004991 is about 40249.2855961444. The cubic root of 1620004991 is about 1174.4614984670.

The spelling of 1620004991 in words is "one billion, six hundred twenty million, four thousand, nine hundred ninety-one".