217491940660 has 48 divisors (see below), whose sum is σ = 464936693760. Its totient is φ = 85445717760.

The previous prime is 217491940657. The next prime is 217491940663. The reversal of 217491940660 is 66049194712.

It is an interprime number because it is at equal distance from previous prime (217491940657) and next prime (217491940663).

It is a super-2 number, since 2×217491940660² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (217491940663) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 58569 + ... + 662128.

It is an arithmetic number, because the mean of its divisors is an integer number (9686181120).

Almost surely, 2^217491940660 is an apocalyptic number.

217491940660 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

217491940660 is an abundant number, since it is smaller than the sum of its proper divisors (247444753100).

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

217491940660 is a wasteful number, since it uses less digits than its factorization.

217491940660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 720976 (or 720974 counting only the distinct ones).

The product of its (nonzero) digits is 653184, while the sum is 49.

The spelling of 217491940660 in words is "two hundred seventeen billion, four hundred ninety-one million, nine hundred forty thousand, six hundred sixty".