1620702217 has 4 divisors (see below), whose sum is σ = 1621342080. Its totient is φ = 1620062356.

The previous prime is 1620702197. The next prime is 1620702247. The reversal of 1620702217 is 7122070261.

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 a de Polignac number, because none of the positive numbers 2^k-1620702217 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1620702247) 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, 316117 + ... + 321202.

It is an arithmetic number, because the mean of its divisors is an integer number (405335520).

Almost surely, 2^1620702217 is an apocalyptic number.

It is an amenable number.

1620702217 is a deficient number, since it is larger than the sum of its proper divisors (639863).

1620702217 is an equidigital number, since it uses as much as digits as its factorization.

1620702217 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 639862.

The product of its (nonzero) digits is 2352, while the sum is 28.

The square root of 1620702217 is about 40257.9460106946. The cubic root of 1620702217 is about 1174.6299645416.

Adding to 1620702217 its reverse (7122070261), we get a palindrome (8742772478).

The spelling of 1620702217 in words is "one billion, six hundred twenty million, seven hundred two thousand, two hundred seventeen".