1561242421651 has 12 divisors (see below), whose sum is σ = 1716334897312. Its totient is φ = 1419097482000.

The previous prime is 1561242421643. The next prime is 1561242421657.

1561242421651 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 1561242421651 - 2³ = 1561242421643 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1561242421657) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 162555 + ... + 1774516.

Almost surely, 2^{1561242421651} is an apocalyptic number.

1561242421651 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1561242421651 is a deficient number, since it is larger than the sum of its proper divisors (155092475661).

1561242421651 is a wasteful number, since it uses less digits than its factorization.

1561242421651 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1943754 (or 1943743 counting only the distinct ones).

The product of its digits is 115200, while the sum is 40.

The spelling of 1561242421651 in words is "one trillion, five hundred sixty-one billion, two hundred forty-two million, four hundred twenty-one thousand, six hundred fifty-one".