1620867599 has 32 divisors (see below), whose sum is σ = 1869127680. Its totient is φ = 1393241472.

The previous prime is 1620867587. The next prime is 1620867641. The reversal of 1620867599 is 9957680261.

It is a Cunningham number, because it is equal to 40260²-1.

It is a cyclic number.

It is not a de Polignac number, because 1620867599 - 2⁸ = 1620867343 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1620867599.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1620867299) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 5112989 + ... + 5113305.

It is an arithmetic number, because the mean of its divisors is an integer number (58410240).

Almost surely, 2^1620867599 is an apocalyptic number.

1620867599 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

1620867599 is a deficient number, since it is larger than the sum of its proper divisors (248260081).

1620867599 is a wasteful number, since it uses less digits than its factorization.

1620867599 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 639.

The product of its (nonzero) digits is 1632960, while the sum is 53.

The square root of 1620867599 is about 40259.9999875807. Note that the first 4 decimals coincide. The cubic root of 1620867599 is about 1174.6699176030.

The spelling of 1620867599 in words is "one billion, six hundred twenty million, eight hundred sixty-seven thousand, five hundred ninety-nine".