1620634513 has 4 divisors (see below), whose sum is σ = 1632464100. Its totient is φ = 1608804928.

The previous prime is 1620634459. The next prime is 1620634517. The reversal of 1620634513 is 3154360261.

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

It can be written as a sum of positive squares in 2 ways, for example, as 955613569 + 665020944 = 30913^2 + 25788^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1620634513 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1620634517) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5914588 + ... + 5914861.

It is an arithmetic number, because the mean of its divisors is an integer number (408116025).

Almost surely, 2^1620634513 is an apocalyptic number.

It is an amenable number.

1620634513 is a deficient number, since it is larger than the sum of its proper divisors (11829587).

1620634513 is a wasteful number, since it uses less digits than its factorization.

1620634513 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11829586.

The product of its (nonzero) digits is 12960, while the sum is 31.

The square root of 1620634513 is about 40257.1051244374. The cubic root of 1620634513 is about 1174.6136077933.

Adding to 1620634513 its reverse (3154360261), we get a palindrome (4774994774).

The spelling of 1620634513 in words is "one billion, six hundred twenty million, six hundred thirty-four thousand, five hundred thirteen".