1561120211651 has 40 divisors (see below), whose sum is σ = 2113505274720. Its totient is φ = 1122882710400.

The previous prime is 1561120211647. The next prime is 1561120211737.

1561120211651 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 1561120211651 - 2² = 1561120211647 is a prime.

It is a super-2 number, since 2×1561120211651² (a number of 25 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1561120211621) 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 39 ways as a sum of consecutive naturals, for example, 746471 + ... + 1918191.

It is an arithmetic number, because the mean of its divisors is an integer number (52837631868).

Almost surely, 2^{1561120211651} is an apocalyptic number.

1561120211651 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1561120211651 is a deficient number, since it is larger than the sum of its proper divisors (552385063069).

1561120211651 is an equidigital number, since it uses as much as digits as its factorization.

1561120211651 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1171785 (or 1171752 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 32.

It can be divided in two parts, 1561120 and 211651, that added together give a palindrome (1772771).

The spelling of 1561120211651 in words is "one trillion, five hundred sixty-one billion, one hundred twenty million, two hundred eleven thousand, six hundred fifty-one".