217534272021 has 36 divisors (see below), whose sum is σ = 360394585824. Its totient is φ = 126106809840.

The previous prime is 217534271959. The next prime is 217534272023. The reversal of 217534272021 is 120272435712.

217534272021 is a `hidden beast` number, since 21 + 7 + 5 + 3 + 427 + 202 + 1 = 666.

It is not a de Polignac number, because 217534272021 - 2⁶ = 217534271957 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (217534272023) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 4317475 + ... + 4367568.

Almost surely, 2^217534272021 is an apocalyptic number.

It is an amenable number.

217534272021 is a deficient number, since it is larger than the sum of its proper divisors (142860313803).

217534272021 is a wasteful number, since it uses less digits than its factorization.

217534272021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8685094 (or 8685080 counting only the distinct ones).

The product of its (nonzero) digits is 47040, while the sum is 36.

It can be divided in two parts, 217534 and 272021, that added together give a triangular number (489555 = T₉₈₉).

The spelling of 217534272021 in words is "two hundred seventeen billion, five hundred thirty-four million, two hundred seventy-two thousand, twenty-one".