1551121551 has 48 divisors (see below), whose sum is σ = 2589350400. Its totient is φ = 876464064.

The previous prime is 1551121547. The next prime is 1551121573. The reversal of 1551121551 is 1551211551.

It is a happy number.

It is not a de Polignac number, because 1551121551 - 2² = 1551121547 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1551121591) 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 47 ways as a sum of consecutive naturals, for example, 3987265 + ... + 3987653.

It is an arithmetic number, because the mean of its divisors is an integer number (53944800).

Almost surely, 2^1551121551 is an apocalyptic number.

1551121551 is a deficient number, since it is larger than the sum of its proper divisors (1038228849).

1551121551 is a wasteful number, since it uses less digits than its factorization.

1551121551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 948 (or 945 counting only the distinct ones).

The product of its digits is 1250, while the sum is 27.

The square root of 1551121551 is about 39384.2805063137. The cubic root of 1551121551 is about 1157.5735921875.

Subtracting 1551121551 from its reverse (1551211551), we obtain a square (90000 = 300²).

The spelling of 1551121551 in words is "one billion, five hundred fifty-one million, one hundred twenty-one thousand, five hundred fifty-one".