216995638 has 8 divisors (see below), whose sum is σ = 325948320. Its totient is φ = 108346200.

The previous prime is 216995579. The next prime is 216995659. The reversal of 216995638 is 836599612.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-2 number, since 2×216995638² = 94174213822054088, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 216995591 and 216995600.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 74013 + ... + 76888.

It is an arithmetic number, because the mean of its divisors is an integer number (40743540).

Almost surely, 2^216995638 is an apocalyptic number.

216995638 is a deficient number, since it is larger than the sum of its proper divisors (108952682).

216995638 is a wasteful number, since it uses less digits than its factorization.

216995638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 151622.

The product of its digits is 699840, while the sum is 49.

The square root of 216995638 is about 14730.7718059849. The cubic root of 216995638 is about 600.9204741937.

The spelling of 216995638 in words is "two hundred sixteen million, nine hundred ninety-five thousand, six hundred thirty-eight".