61271640 has 80 divisors (see below), whose sum is σ = 205951680. Its totient is φ = 16338240.

The previous prime is 61271629. The next prime is 61271641. The reversal of 61271640 is 4617216.

61271640 is a `hidden beast` number, since 6 + 12 + 7 + 1 + 640 = 666.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61271641) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 6216 + ... + 12695.

It is an arithmetic number, because the mean of its divisors is an integer number (2574396).

Almost surely, 2^61271640 is an apocalyptic number.

61271640 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

61271640 is an abundant number, since it is smaller than the sum of its proper divisors (144680040).

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

61271640 is a wasteful number, since it uses less digits than its factorization.

61271640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18934 (or 18921 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 27.

The square root of 61271640 is about 7827.6203280435. The cubic root of 61271640 is about 394.2331755542.

Adding to 61271640 its reverse (4617216), we get a palindrome (65888856).

The spelling of 61271640 in words is "sixty-one million, two hundred seventy-one thousand, six hundred forty".