215361551 has 4 divisors (see below), whose sum is σ = 215622792. Its totient is φ = 215100312.

The previous prime is 215361541. The next prime is 215361611. The reversal of 215361551 is 155163512.

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

It is a cyclic number.

It is not a de Polignac number, because 215361551 - 2¹⁰ = 215360527 is a prime.

It is a super-4 number, since 4×215361551⁴ (a number of 34 digits) contains 4444 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 (215361541) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 129380 + ... + 131033.

It is an arithmetic number, because the mean of its divisors is an integer number (53905698).

Almost surely, 2^215361551 is an apocalyptic number.

215361551 is a deficient number, since it is larger than the sum of its proper divisors (261241).

215361551 is an equidigital number, since it uses as much as digits as its factorization.

215361551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 261240.

The product of its digits is 4500, while the sum is 29.

The square root of 215361551 is about 14675.2019066178. The cubic root of 215361551 is about 599.4082601169.

The spelling of 215361551 in words is "two hundred fifteen million, three hundred sixty-one thousand, five hundred fifty-one".