1620388501 has 4 divisors (see below), whose sum is σ = 1644573472. Its totient is φ = 1596203532.

The previous prime is 1620388459. The next prime is 1620388531. The reversal of 1620388501 is 1058830261.

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.

It is a cyclic number.

It is not a de Polignac number, because 1620388501 - 2¹⁵ = 1620355733 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 (1620388531) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12092385 + ... + 12092518.

It is an arithmetic number, because the mean of its divisors is an integer number (411143368).

Almost surely, 2^1620388501 is an apocalyptic number.

It is an amenable number.

1620388501 is a deficient number, since it is larger than the sum of its proper divisors (24184971).

1620388501 is an equidigital number, since it uses as much as digits as its factorization.

1620388501 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24184970.

The product of its (nonzero) digits is 11520, while the sum is 34.

The square root of 1620388501 is about 40254.0494981561. The cubic root of 1620388501 is about 1174.5541694142.

The spelling of 1620388501 in words is "one billion, six hundred twenty million, three hundred eighty-eight thousand, five hundred one".