61231220 has 12 divisors (see below), whose sum is σ = 128585604. Its totient is φ = 24492480.

The previous prime is 61231213. The next prime is 61231223. The reversal of 61231220 is 2213216.

It can be written as a sum of positive squares in 2 ways, for example, as 30184036 + 31047184 = 5494^2 + 5572^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61231223) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1530761 + ... + 1530800.

It is an arithmetic number, because the mean of its divisors is an integer number (10715467).

Almost surely, 2^61231220 is an apocalyptic number.

It is an amenable number.

61231220 is an abundant number, since it is smaller than the sum of its proper divisors (67354384).

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

61231220 is a wasteful number, since it uses less digits than its factorization.

61231220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3061570 (or 3061568 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 17.

The square root of 61231220 is about 7825.0380190770. The cubic root of 61231220 is about 394.1464665414.

Adding to 61231220 its reverse (2213216), we get a palindrome (63444436).

The spelling of 61231220 in words is "sixty-one million, two hundred thirty-one thousand, two hundred twenty".