77440081 has 4 divisors (see below), whose sum is σ = 77659812. Its totient is φ = 77220352.

The previous prime is 77440061. The next prime is 77440123. The reversal of 77440081 is 18004477.

77440081 = T₄₇₈ + T₄₇₉ + ... + T₈₃₀.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 31539456 + 45900625 = 5616^2 + 6775^2 .

It is a cyclic number.

It is not a de Polignac number, because 77440081 - 2¹⁵ = 77407313 is a prime.

It is a super-2 number, since 2×77440081² = 11993932290573122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (77440061) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 109336 + ... + 110041.

It is an arithmetic number, because the mean of its divisors is an integer number (19414953).

Almost surely, 2^77440081 is an apocalyptic number.

It is an amenable number.

77440081 is a deficient number, since it is larger than the sum of its proper divisors (219731).

77440081 is a wasteful number, since it uses less digits than its factorization.

77440081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 219730.

The product of its (nonzero) digits is 6272, while the sum is 31.

The square root of 77440081 is about 8800.0046022715. The cubic root of 77440081 is about 426.2410433185.

It can be divided in two parts, 774400 and 81, that multiplied together give a square (62726400 = 7920²).

The spelling of 77440081 in words is "seventy-seven million, four hundred forty thousand, eighty-one".