215187381 has 16 divisors (see below), whose sum is σ = 319032000. Its totient is φ = 143352144.

The previous prime is 215187361. The next prime is 215187391. The reversal of 215187381 is 183781512.

It is not a de Polignac number, because 215187381 - 2⁷ = 215187253 is a prime.

It is a super-2 number, since 2×215187381² = 92611217883278322, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (215187361) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 54775 + ... + 58571.

It is an arithmetic number, because the mean of its divisors is an integer number (19939500).

Almost surely, 2^215187381 is an apocalyptic number.

It is an amenable number.

215187381 is a deficient number, since it is larger than the sum of its proper divisors (103844619).

215187381 is a wasteful number, since it uses less digits than its factorization.

215187381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5905 (or 5899 counting only the distinct ones).

The product of its digits is 13440, while the sum is 36.

The square root of 215187381 is about 14669.2665460820. The cubic root of 215187381 is about 599.2466294506.

The spelling of 215187381 in words is "two hundred fifteen million, one hundred eighty-seven thousand, three hundred eighty-one".