1551561149 has 4 divisors (see below), whose sum is σ = 1554288540. Its totient is φ = 1548833760.

The previous prime is 1551561113. The next prime is 1551561197. The reversal of 1551561149 is 9411651551.

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 333062500 + 1218498649 = 18250^2 + 34907^2 .

It is a cyclic number.

It is not a de Polignac number, because 1551561149 - 2²⁰ = 1550512573 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1551560149) 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, 1362842 + ... + 1363979.

It is an arithmetic number, because the mean of its divisors is an integer number (388572135).

Almost surely, 2^1551561149 is an apocalyptic number.

It is an amenable number.

1551561149 is a deficient number, since it is larger than the sum of its proper divisors (2727391).

1551561149 is an equidigital number, since it uses as much as digits as its factorization.

1551561149 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2727390.

The product of its digits is 27000, while the sum is 38.

The square root of 1551561149 is about 39389.8609923924. The cubic root of 1551561149 is about 1157.6829365027.

The spelling of 1551561149 in words is "one billion, five hundred fifty-one million, five hundred sixty-one thousand, one hundred forty-nine".