210561397 has 4 divisors (see below), whose sum is σ = 210652576. Its totient is φ = 210470220.

The previous prime is 210561361. The next prime is 210561443. The reversal of 210561397 is 793165012.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-210561397 is a prime.

It is a super-2 number, since 2×210561397² = 88672203813183218, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (210561317) 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, 42033 + ... + 46774.

It is an arithmetic number, because the mean of its divisors is an integer number (52663144).

Almost surely, 2^210561397 is an apocalyptic number.

It is an amenable number.

210561397 is a deficient number, since it is larger than the sum of its proper divisors (91179).

210561397 is an equidigital number, since it uses as much as digits as its factorization.

210561397 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 91178.

The product of its (nonzero) digits is 11340, while the sum is 34.

The square root of 210561397 is about 14510.7338546333. The cubic root of 210561397 is about 594.9213906459.

The spelling of 210561397 in words is "two hundred ten million, five hundred sixty-one thousand, three hundred ninety-seven".