77994991 has 16 divisors (see below), whose sum is σ = 82494720. Its totient is φ = 73664640.

The previous prime is 77994979. The next prime is 77995003. The reversal of 77994991 is 19949977.

It is an interprime number because it is at equal distance from previous prime (77994979) and next prime (77995003).

It is a cyclic number.

It is not a de Polignac number, because 77994991 - 2¹⁵ = 77962223 is a prime.

It is a super-3 number, since 3×77994991³ (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 (77994941) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 179911 + ... + 180343.

It is an arithmetic number, because the mean of its divisors is an integer number (5155920).

Almost surely, 2^77994991 is an apocalyptic number.

77994991 is a gapful number since it is divisible by the number (71) formed by its first and last digit.

77994991 is a deficient number, since it is larger than the sum of its proper divisors (4499729).

77994991 is a wasteful number, since it uses less digits than its factorization.

77994991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 606.

The product of its digits is 1285956, while the sum is 55.

The square root of 77994991 is about 8831.4772829918. The cubic root of 77994991 is about 427.2567219281.

The spelling of 77994991 in words is "seventy-seven million, nine hundred ninety-four thousand, nine hundred ninety-one".