690824786621 has 2 divisors, whose sum is σ = 690824786622. Its totient is φ = 690824786620.

The previous prime is 690824786609. The next prime is 690824786627. The reversal of 690824786621 is 126687428096.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 505434261721 + 185390524900 = 710939^2 + 430570^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-690824786621 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (690824786627) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 345412393310 + 345412393311.

It is an arithmetic number, because the mean of its divisors is an integer number (345412393311).

Almost surely, 2^690824786621 is an apocalyptic number.

It is an amenable number.

690824786621 is a deficient number, since it is larger than the sum of its proper divisors (1).

690824786621 is an equidigital number, since it uses as much as digits as its factorization.

690824786621 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 13934592, while the sum is 59.

The spelling of 690824786621 in words is "six hundred ninety billion, eight hundred twenty-four million, seven hundred eighty-six thousand, six hundred twenty-one".