1620691243 has 16 divisors (see below), whose sum is σ = 1739849760. Its totient is φ = 1504313856.

The previous prime is 1620691217. The next prime is 1620691291. The reversal of 1620691243 is 3421960261.

It is a happy number.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1620691243 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1620691199 and 1620691208.

It is not an unprimeable number, because it can be changed into a prime (1620691643) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 418705 + ... + 422557.

It is an arithmetic number, because the mean of its divisors is an integer number (108740610).

Almost surely, 2^1620691243 is an apocalyptic number.

1620691243 is a deficient number, since it is larger than the sum of its proper divisors (119158517).

1620691243 is a wasteful number, since it uses less digits than its factorization.

1620691243 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4206.

The product of its (nonzero) digits is 15552, while the sum is 34.

The square root of 1620691243 is about 40257.8097143896. The cubic root of 1620691243 is about 1174.6273133413.

The spelling of 1620691243 in words is "one billion, six hundred twenty million, six hundred ninety-one thousand, two hundred forty-three".