72777478 has 4 divisors (see below), whose sum is σ = 109166220. Its totient is φ = 36388738.

The previous prime is 72777473. The next prime is 72777499. The reversal of 72777478 is 87477727.

It is a happy number.

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

It is a super-2 number, since 2×72777478² = 10593122608080968, which contains 22 as substring.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72777473) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 18194368 + ... + 18194371.

It is an arithmetic number, because the mean of its divisors is an integer number (27291555).

Almost surely, 2^72777478 is an apocalyptic number.

72777478 is a deficient number, since it is larger than the sum of its proper divisors (36388742).

72777478 is a wasteful number, since it uses less digits than its factorization.

72777478 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36388741.

The product of its digits is 1075648, while the sum is 49.

The square root of 72777478 is about 8530.9716914312. The cubic root of 72777478 is about 417.5088322082.

The spelling of 72777478 in words is "seventy-two million, seven hundred seventy-seven thousand, four hundred seventy-eight".