215556797 has 4 divisors (see below), whose sum is σ = 222989820. Its totient is φ = 208123776.

The previous prime is 215556791. The next prime is 215556823. The reversal of 215556797 is 797655512.

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 69122596 + 146434201 = 8314^2 + 12101^2 .

It is a cyclic number.

It is not a de Polignac number, because 215556797 - 2²² = 211362493 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (215556791) 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, 3716468 + ... + 3716525.

It is an arithmetic number, because the mean of its divisors is an integer number (55747455).

Almost surely, 2^215556797 is an apocalyptic number.

It is an amenable number.

215556797 is a deficient number, since it is larger than the sum of its proper divisors (7433023).

215556797 is an equidigital number, since it uses as much as digits as its factorization.

215556797 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7433022.

The product of its digits is 661500, while the sum is 47.

The square root of 215556797 is about 14681.8526419522. The cubic root of 215556797 is about 599.5893458546.

The spelling of 215556797 in words is "two hundred fifteen million, five hundred fifty-six thousand, seven hundred ninety-seven".