78446781 has 12 divisors (see below), whose sum is σ = 129499552. Its totient is φ = 44826696.

The previous prime is 78446743. The next prime is 78446783. The reversal of 78446781 is 18764487.

It is not a de Polignac number, because 78446781 - 2¹¹ = 78444733 is a prime.

It is a super-2 number, since 2×78446781² = 12307794898523922, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78446783) 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, 622531 + ... + 622656.

Almost surely, 2^78446781 is an apocalyptic number.

It is an amenable number.

78446781 is a deficient number, since it is larger than the sum of its proper divisors (51052771).

78446781 is a wasteful number, since it uses less digits than its factorization.

78446781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1245200 (or 1245197 counting only the distinct ones).

The product of its digits is 301056, while the sum is 45.

The square root of 78446781 is about 8857.0187422179. The cubic root of 78446781 is about 428.0801029943.

The spelling of 78446781 in words is "seventy-eight million, four hundred forty-six thousand, seven hundred eighty-one".