77217481 has 6 divisors (see below), whose sum is σ = 84875546. Its totient is φ = 70197600.

The previous prime is 77217461. The next prime is 77217493. The reversal of 77217481 is 18471277.

It can be written as a sum of positive squares in only one way, i.e., 41409225 + 35808256 = 6435^2 + 5984^2 .

It is not a de Polignac number, because 77217481 - 2¹¹ = 77215433 is a prime.

It is a super-2 number, since 2×77217481² = 11925078743970722, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 77217481.

It is not an unprimeable number, because it can be changed into a prime (77217421) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 318960 + ... + 319201.

Almost surely, 2^77217481 is an apocalyptic number.

It is an amenable number.

77217481 is a deficient number, since it is larger than the sum of its proper divisors (7658065).

77217481 is a wasteful number, since it uses less digits than its factorization.

77217481 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 638183 (or 638172 counting only the distinct ones).

The product of its digits is 21952, while the sum is 37.

The square root of 77217481 is about 8787.3477796204. The cubic root of 77217481 is about 425.8322441888.

The spelling of 77217481 in words is "seventy-seven million, two hundred seventeen thousand, four hundred eighty-one".