217987628 has 6 divisors (see below), whose sum is σ = 381478356. Its totient is φ = 108993812.

The previous prime is 217987621. The next prime is 217987669. The reversal of 217987628 is 826789712.

It is a super-2 number, since 2×217987628² = 95037211922132768, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (217987621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27248450 + ... + 27248457.

It is an arithmetic number, because the mean of its divisors is an integer number (63579726).

Almost surely, 2^217987628 is an apocalyptic number.

It is an amenable number.

217987628 is a deficient number, since it is larger than the sum of its proper divisors (163490728).

217987628 is a wasteful number, since it uses less digits than its factorization.

217987628 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54496911 (or 54496909 counting only the distinct ones).

The product of its digits is 677376, while the sum is 50.

The square root of 217987628 is about 14764.4040855024. The cubic root of 217987628 is about 601.8347798818.

The spelling of 217987628 in words is "two hundred seventeen million, nine hundred eighty-seven thousand, six hundred twenty-eight".