217420764 has 24 divisors (see below), whose sum is σ = 553435008. Its totient is φ = 65885040.

The previous prime is 217420759. The next prime is 217420789. The reversal of 217420764 is 467024712.

It is a Harshad number since it is a multiple of its sum of digits (33).

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 7 ways as a sum of consecutive naturals, for example, 823432 + ... + 823695.

It is an arithmetic number, because the mean of its divisors is an integer number (23059792).

Almost surely, 2^217420764 is an apocalyptic number.

It is an amenable number.

217420764 is an abundant number, since it is smaller than the sum of its proper divisors (336014244).

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

217420764 is a wasteful number, since it uses less digits than its factorization.

217420764 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1647145 (or 1647143 counting only the distinct ones).

The product of its (nonzero) digits is 18816, while the sum is 33.

The square root of 217420764 is about 14745.1946070576. The cubic root of 217420764 is about 601.3126483850.

The spelling of 217420764 in words is "two hundred seventeen million, four hundred twenty thousand, seven hundred sixty-four".