209648531 has 2 divisors, whose sum is σ = 209648532. Its totient is φ = 209648530.

The previous prime is 209648479. The next prime is 209648563. The reversal of 209648531 is 135846902.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-209648531 is a prime.

It is a super-2 number, since 2×209648531² = 87905013100915922, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (209648591) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 104824265 + 104824266.

It is an arithmetic number, because the mean of its divisors is an integer number (104824266).

Almost surely, 2^209648531 is an apocalyptic number.

209648531 is a deficient number, since it is larger than the sum of its proper divisors (1).

209648531 is an equidigital number, since it uses as much as digits as its factorization.

209648531 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 51840, while the sum is 38.

The square root of 209648531 is about 14479.2448352806. The cubic root of 209648531 is about 594.0604062486.

The spelling of 209648531 in words is "two hundred nine million, six hundred forty-eight thousand, five hundred thirty-one".