217380977 has 12 divisors (see below), whose sum is σ = 241415748. Its totient is φ = 195571200.

The previous prime is 217380967. The next prime is 217380979. The reversal of 217380977 is 779083712.

It can be written as a sum of positive squares in 2 ways, for example, as 175403536 + 41977441 = 13244^2 + 6479^2 .

It is not a de Polignac number, because 217380977 - 2¹² = 217376881 is a prime.

It is a super-2 number, since 2×217380977² = 94508978322949058, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (217380979) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2477 + ... + 20997.

It is an arithmetic number, because the mean of its divisors is an integer number (20117979).

Almost surely, 2^217380977 is an apocalyptic number.

It is an amenable number.

217380977 is a deficient number, since it is larger than the sum of its proper divisors (24034771).

217380977 is a wasteful number, since it uses less digits than its factorization.

217380977 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18640 (or 18629 counting only the distinct ones).

The product of its (nonzero) digits is 148176, while the sum is 44.

The square root of 217380977 is about 14743.8453939262. The cubic root of 217380977 is about 601.2759669976.

The spelling of 217380977 in words is "two hundred seventeen million, three hundred eighty thousand, nine hundred seventy-seven".