61777440 has 72 divisors (see below), whose sum is σ = 210820428. Its totient is φ = 16473600.

The previous prime is 61777433. The next prime is 61777483. The reversal of 61777440 is 4477716.

It can be written as a sum of positive squares in 2 ways, for example, as 61402896 + 374544 = 7836^2 + 612^2 .

It is a tau number, because it is divible by the number of its divisors (72).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 61777395 and 61777404.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 20011 + ... + 22890.

Almost surely, 2^61777440 is an apocalyptic number.

61777440 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

61777440 is an abundant number, since it is smaller than the sum of its proper divisors (149042988).

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

61777440 is a wasteful number, since it uses less digits than its factorization.

61777440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42922 (or 42911 counting only the distinct ones).

The product of its (nonzero) digits is 32928, while the sum is 36.

The square root of 61777440 is about 7859.8625942188. The cubic root of 61777440 is about 395.3150080246.

The spelling of 61777440 in words is "sixty-one million, seven hundred seventy-seven thousand, four hundred forty".