217742073680 has 20 divisors (see below), whose sum is σ = 506250321492. Its totient is φ = 87096829440.

The previous prime is 217742073677. The next prime is 217742073727. The reversal of 217742073680 is 86370247712.

It can be written as a sum of positive squares in 2 ways, for example, as 104647074064 + 113094999616 = 323492^2 + 336296^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a super-2 number, since 2×217742073680² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1360887881 + ... + 1360888040.

Almost surely, 2^217742073680 is an apocalyptic number.

217742073680 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

217742073680 is an abundant number, since it is smaller than the sum of its proper divisors (288508247812).

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

217742073680 is a wasteful number, since it uses less digits than its factorization.

217742073680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2721775934 (or 2721775928 counting only the distinct ones).

The product of its (nonzero) digits is 790272, while the sum is 47.

The spelling of 217742073680 in words is "two hundred seventeen billion, seven hundred forty-two million, seventy-three thousand, six hundred eighty".