1620164731 has 4 divisors (see below), whose sum is σ = 1639684872. Its totient is φ = 1600644592.

The previous prime is 1620164729. The next prime is 1620164737. The reversal of 1620164731 is 1374610261.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1620164731 - 2¹ = 1620164729 is a prime.

It is a super-2 number, since 2×1620164731² = 5249867511152604722, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1620164693 and 1620164702.

It is not an unprimeable number, because it can be changed into a prime (1620164737) 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, 9759946 + ... + 9760111.

It is an arithmetic number, because the mean of its divisors is an integer number (409921218).

Almost surely, 2^1620164731 is an apocalyptic number.

1620164731 is a deficient number, since it is larger than the sum of its proper divisors (19520141).

1620164731 is an equidigital number, since it uses as much as digits as its factorization.

1620164731 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19520140.

The product of its (nonzero) digits is 6048, while the sum is 31.

The square root of 1620164731 is about 40251.2699302767. The cubic root of 1620164731 is about 1174.5000996472.

Adding to 1620164731 its reverse (1374610261), we get a palindrome (2994774992).

The spelling of 1620164731 in words is "one billion, six hundred twenty million, one hundred sixty-four thousand, seven hundred thirty-one".