1561622651 has 4 divisors (see below), whose sum is σ = 1629519312. Its totient is φ = 1493725992.

The previous prime is 1561622633. The next prime is 1561622663. The reversal of 1561622651 is 1562261651.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1561622651 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1561612651) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 33948296 + ... + 33948341.

It is an arithmetic number, because the mean of its divisors is an integer number (407379828).

Almost surely, 2^1561622651 is an apocalyptic number.

1561622651 is a deficient number, since it is larger than the sum of its proper divisors (67896661).

1561622651 is an equidigital number, since it uses as much as digits as its factorization.

1561622651 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 67896660.

The product of its digits is 21600, while the sum is 35.

The square root of 1561622651 is about 39517.3715092489. The cubic root of 1561622651 is about 1160.1799787626.

The spelling of 1561622651 in words is "one billion, five hundred sixty-one million, six hundred twenty-two thousand, six hundred fifty-one".