245806991 has 2 divisors, whose sum is σ = 245806992. Its totient is φ = 245806990.

The previous prime is 245806973. The next prime is 245807017. The reversal of 245806991 is 199608542.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 245806991 - 2²⁶ = 178698127 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 (245806091) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 122903495 + 122903496.

It is an arithmetic number, because the mean of its divisors is an integer number (122903496).

Almost surely, 2^245806991 is an apocalyptic number.

245806991 is a deficient number, since it is larger than the sum of its proper divisors (1).

245806991 is an equidigital number, since it uses as much as digits as its factorization.

245806991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 155520, while the sum is 44.

The square root of 245806991 is about 15678.2330318183. The cubic root of 245806991 is about 626.4187426872.

The spelling of 245806991 in words is "two hundred forty-five million, eight hundred six thousand, nine hundred ninety-one".