217989690 has 32 divisors (see below), whose sum is σ = 525125376. Its totient is φ = 57913920.

The previous prime is 217989683. The next prime is 217989701. The reversal of 217989690 is 96989712.

It is a happy number.

It is a super-2 number, since 2×217989690² = 95039009892592200, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5277 + ... + 21536.

It is an arithmetic number, because the mean of its divisors is an integer number (16410168).

Almost surely, 2^217989690 is an apocalyptic number.

217989690 is an abundant number, since it is smaller than the sum of its proper divisors (307135686).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

217989690 is a wasteful number, since it uses less digits than its factorization.

217989690 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27094.

The product of its (nonzero) digits is 489888, while the sum is 51.

The square root of 217989690 is about 14764.4739154499. The cubic root of 217989690 is about 601.8366775116.

The spelling of 217989690 in words is "two hundred seventeen million, nine hundred eighty-nine thousand, six hundred ninety".