77400522 has 60 divisors (see below), whose sum is σ = 178759350. Its totient is φ = 25030944.

The previous prime is 77400481. The next prime is 77400523. The reversal of 77400522 is 22500477.

77400522 = 439² + 440² + ... + 681².

It can be written as a sum of positive squares in 3 ways, for example, as 74805201 + 2595321 = 8649^2 + 1611^2 .

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (77400523) by changing a digit.

It is a polite number, since it can be written in 29 ways as a sum of consecutive naturals, for example, 221604 + ... + 221952.

Almost surely, 2^77400522 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 77400522, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (89379675).

77400522 is an abundant number, since it is smaller than the sum of its proper divisors (101358828).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

77400522 is a wasteful number, since it uses less digits than its factorization.

77400522 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 437 (or 391 counting only the distinct ones).

The product of its (nonzero) digits is 3920, while the sum is 27.

The square root of 77400522 is about 8797.7566458729. The cubic root of 77400522 is about 426.1684515322.

Adding to 77400522 its reverse (22500477), we get a palindrome (99900999).

The spelling of 77400522 in words is "seventy-seven million, four hundred thousand, five hundred twenty-two".