61777920 has 96 divisors (see below), whose sum is σ = 197739360. Its totient is φ = 16465920.

The previous prime is 61777889. The next prime is 61777943. The reversal of 61777920 is 2977716.

It is a tau number, because it is divible by the number of its divisors (96).

It is a super-2 number, since 2×61777920² = 7633022799052800, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 29715 + ... + 31725.

It is an arithmetic number, because the mean of its divisors is an integer number (2059785).

Almost surely, 2^61777920 is an apocalyptic number.

61777920 is a gapful number since it is divisible by the number (60) 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 61777920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (98869680).

61777920 is an abundant number, since it is smaller than the sum of its proper divisors (135961440).

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

61777920 is a wasteful number, since it uses less digits than its factorization.

61777920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2041 (or 2021 counting only the distinct ones).

The product of its (nonzero) digits is 37044, while the sum is 39.

The square root of 61777920 is about 7859.8931290444. The cubic root of 61777920 is about 395.3160318650.

The spelling of 61777920 in words is "sixty-one million, seven hundred seventy-seven thousand, nine hundred twenty".