51491603 has 2 divisors, whose sum is σ = 51491604. Its totient is φ = 51491602.

The previous prime is 51491599. The next prime is 51491621. The reversal of 51491603 is 30619415.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 51491603 - 2² = 51491599 is a prime.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (51491633) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25745801 + 25745802.

It is an arithmetic number, because the mean of its divisors is an integer number (25745802).

Almost surely, 2^51491603 is an apocalyptic number.

51491603 is a deficient number, since it is larger than the sum of its proper divisors (1).

51491603 is an equidigital number, since it uses as much as digits as its factorization.

51491603 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3240, while the sum is 29.

The square root of 51491603 is about 7175.7649766419. The cubic root of 51491603 is about 372.0307211496.

The spelling of 51491603 in words is "fifty-one million, four hundred ninety-one thousand, six hundred three".