77561400 has 192 divisors, whose sum is σ = 280339200. Its totient is φ = 17372160.

The previous prime is 77561387. The next prime is 77561441. The reversal of 77561400 is 416577.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 247644 + ... + 247956.

It is an arithmetic number, because the mean of its divisors is an integer number (1460100).

Almost surely, 2^77561400 is an apocalyptic number.

77561400 is a gapful number since it is divisible by the number (70) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 77561400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (140169600).

77561400 is an abundant number, since it is smaller than the sum of its proper divisors (202777800).

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

77561400 is a wasteful number, since it uses less digits than its factorization.

77561400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 398 (or 389 counting only the distinct ones).

The product of its (nonzero) digits is 5880, while the sum is 30.

The square root of 77561400 is about 8806.8950260577. The cubic root of 77561400 is about 426.4635127688.

Adding to 77561400 its reverse (416577), we get a palindrome (77977977).

The spelling of 77561400 in words is "seventy-seven million, five hundred sixty-one thousand, four hundred".