213025661 has 4 divisors (see below), whose sum is σ = 213276252. Its totient is φ = 212775072.

The previous prime is 213025639. The next prime is 213025711. The reversal of 213025661 is 166520312.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 106296100 + 106729561 = 10310^2 + 10331^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-213025661 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 213025661.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (213025601) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 124016 + ... + 125721.

It is an arithmetic number, because the mean of its divisors is an integer number (53319063).

Almost surely, 2^213025661 is an apocalyptic number.

It is an amenable number.

213025661 is a deficient number, since it is larger than the sum of its proper divisors (250591).

213025661 is an equidigital number, since it uses as much as digits as its factorization.

213025661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 250590.

The product of its (nonzero) digits is 2160, while the sum is 26.

The square root of 213025661 is about 14595.3986242240. The cubic root of 213025661 is about 597.2332437847.

Adding to 213025661 its reverse (166520312), we get a palindrome (379545973).

The spelling of 213025661 in words is "two hundred thirteen million, twenty-five thousand, six hundred sixty-one".