77472221 has 4 divisors (see below), whose sum is σ = 78063744. Its totient is φ = 76880700.

The previous prime is 77472217. The next prime is 77472223. The reversal of 77472221 is 12227477.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 12227477 = 83 ⋅147319.

It is a cyclic number.

It is not a de Polignac number, because 77472221 - 2² = 77472217 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77472223) 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, 295565 + ... + 295826.

It is an arithmetic number, because the mean of its divisors is an integer number (19515936).

Almost surely, 2^77472221 is an apocalyptic number.

It is an amenable number.

77472221 is a deficient number, since it is larger than the sum of its proper divisors (591523).

77472221 is a wasteful number, since it uses less digits than its factorization.

77472221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 591522.

The product of its digits is 10976, while the sum is 32.

The square root of 77472221 is about 8801.8305482439. The cubic root of 77472221 is about 426.3000028485.

Adding to 77472221 its reverse (12227477), we get a palindrome (89699698).

The spelling of 77472221 in words is "seventy-seven million, four hundred seventy-two thousand, two hundred twenty-one".