2451991 has 2 divisors, whose sum is σ = 2451992. Its totient is φ = 2451990.

The previous prime is 2451973. The next prime is 2452003. The reversal of 2451991 is 1991542.

2451991 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 2451991 - 2¹⁹ = 1927703 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2451941) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1225995 + 1225996.

It is an arithmetic number, because the mean of its divisors is an integer number (1225996).

2^2451991 is an apocalyptic number.

2451991 is a deficient number, since it is larger than the sum of its proper divisors (1).

2451991 is an equidigital number, since it uses as much as digits as its factorization.

2451991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3240, while the sum is 31.

The square root of 2451991 is about 1565.8834567106. The cubic root of 2451991 is about 134.8464830141.

The spelling of 2451991 in words is "two million, four hundred fifty-one thousand, nine hundred ninety-one".