15561651551 has 4 divisors (see below), whose sum is σ = 15855267672. Its totient is φ = 15268035432.

The previous prime is 15561651541. The next prime is 15561651559. The reversal of 15561651551 is 15515616551.

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

It is a cyclic number.

It is not a de Polignac number, because 15561651551 - 2⁶ = 15561651487 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 15561651499 and 15561651508.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15561651559) 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, 146807981 + ... + 146808086.

It is an arithmetic number, because the mean of its divisors is an integer number (3963816918).

Almost surely, 2^15561651551 is an apocalyptic number.

15561651551 is a deficient number, since it is larger than the sum of its proper divisors (293616121).

15561651551 is an equidigital number, since it uses as much as digits as its factorization.

15561651551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 293616120.

The product of its digits is 112500, while the sum is 41.

The spelling of 15561651551 in words is "fifteen billion, five hundred sixty-one million, six hundred fifty-one thousand, five hundred fifty-one".