61031220 has 48 divisors (see below), whose sum is σ = 171678528. Its totient is φ = 16199680.

The previous prime is 61031203. The next prime is 61031227. The reversal of 61031220 is 2213016.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 61031220.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61031227) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11380 + ... + 15860.

It is an arithmetic number, because the mean of its divisors is an integer number (3576636).

Almost surely, 2^61031220 is an apocalyptic number.

61031220 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

61031220 is an abundant number, since it is smaller than the sum of its proper divisors (110647308).

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

61031220 is a wasteful number, since it uses less digits than its factorization.

61031220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4720 (or 4718 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 15.

The square root of 61031220 is about 7812.2480759382. The cubic root of 61031220 is about 393.7168639286.

Adding to 61031220 its reverse (2213016), we get a palindrome (63244236).

The spelling of 61031220 in words is "sixty-one million, thirty-one thousand, two hundred twenty".