690971509 has 2 divisors, whose sum is σ = 690971510. Its totient is φ = 690971508.

The previous prime is 690971473. The next prime is 690971527. The reversal of 690971509 is 905179096.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 624500100 + 66471409 = 24990^2 + 8153^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-690971509 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (690971539) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 345485754 + 345485755.

It is an arithmetic number, because the mean of its divisors is an integer number (345485755).

Almost surely, 2^690971509 is an apocalyptic number.

It is an amenable number.

690971509 is a deficient number, since it is larger than the sum of its proper divisors (1).

690971509 is an equidigital number, since it uses as much as digits as its factorization.

690971509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 153090, while the sum is 46.

The square root of 690971509 is about 26286.3369262436. The cubic root of 690971509 is about 884.0701220796.

The spelling of 690971509 in words is "six hundred ninety million, nine hundred seventy-one thousand, five hundred nine".