215551620061 has 4 divisors (see below), whose sum is σ = 215555194492. Its totient is φ = 215548045632.

The previous prime is 215551620019. The next prime is 215551620073. The reversal of 215551620061 is 160026155512.

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 198497871961 + 17053748100 = 445531^2 + 130590^2 .

It is a cyclic number.

It is not a de Polignac number, because 215551620061 - 2²⁵ = 215518065629 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 215551619999 and 215551620026.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (215551627061) 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, 1695180 + ... + 1817893.

It is an arithmetic number, because the mean of its divisors is an integer number (53888798623).

Almost surely, 2^215551620061 is an apocalyptic number.

It is an amenable number.

215551620061 is a deficient number, since it is larger than the sum of its proper divisors (3574431).

215551620061 is an equidigital number, since it uses as much as digits as its factorization.

215551620061 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3574430.

The product of its (nonzero) digits is 18000, while the sum is 34.

Adding to 215551620061 its reverse (160026155512), we get a palindrome (375577775573).

The spelling of 215551620061 in words is "two hundred fifteen billion, five hundred fifty-one million, six hundred twenty thousand, sixty-one".