77978887 has 8 divisors (see below), whose sum is σ = 89207456. Its totient is φ = 66772512.

The previous prime is 77978839. The next prime is 77978897. The reversal of 77978887 is 78887977.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 77978887 - 2¹⁵ = 77946119 is a prime.

It is a super-3 number, since 3×77978887³ (a number of 25 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77978807) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2833 + ... + 12805.

It is an arithmetic number, because the mean of its divisors is an integer number (11150932).

Almost surely, 2^77978887 is an apocalyptic number.

77978887 is a deficient number, since it is larger than the sum of its proper divisors (11228569).

77978887 is a wasteful number, since it uses less digits than its factorization.

77978887 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11097.

The product of its digits is 11063808, while the sum is 61.

The square root of 77978887 is about 8830.5654971808. The cubic root of 77978887 is about 427.2273139889.

The spelling of 77978887 in words is "seventy-seven million, nine hundred seventy-eight thousand, eight hundred eighty-seven".