1551099391 has 2 divisors, whose sum is σ = 1551099392. Its totient is φ = 1551099390.

The previous prime is 1551099373. The next prime is 1551099437. The reversal of 1551099391 is 1939901551.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1551099391 - 2¹¹ = 1551097343 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1551099301) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 775549695 + 775549696.

It is an arithmetic number, because the mean of its divisors is an integer number (775549696).

Almost surely, 2^1551099391 is an apocalyptic number.

1551099391 is a deficient number, since it is larger than the sum of its proper divisors (1).

1551099391 is an equidigital number, since it uses as much as digits as its factorization.

1551099391 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 54675, while the sum is 43.

The square root of 1551099391 is about 39383.9991747918. Note that the first 3 decimals coincide. The cubic root of 1551099391 is about 1157.5680796272.

The spelling of 1551099391 in words is "one billion, five hundred fifty-one million, ninety-nine thousand, three hundred ninety-one".