1551045991 has 16 divisors (see below), whose sum is σ = 1748596608. Its totient is φ = 1363572000.

The previous prime is 1551045959. The next prime is 1551046027. The reversal of 1551045991 is 1995401551.

It is a cyclic number.

It is not a de Polignac number, because 1551045991 - 2⁵ = 1551045959 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1551045941) 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 15 ways as a sum of consecutive naturals, for example, 31540 + ... + 64006.

It is an arithmetic number, because the mean of its divisors is an integer number (109287288).

Almost surely, 2^1551045991 is an apocalyptic number.

1551045991 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1551045991 is a deficient number, since it is larger than the sum of its proper divisors (197550617).

1551045991 is a wasteful number, since it uses less digits than its factorization.

1551045991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32622.

The product of its (nonzero) digits is 40500, while the sum is 40.

The square root of 1551045991 is about 39383.3212286623. The cubic root of 1551045991 is about 1157.5547955344.

The spelling of 1551045991 in words is "one billion, five hundred fifty-one million, forty-five thousand, nine hundred ninety-one".