71631220 has 24 divisors (see below), whose sum is σ = 151919208. Its totient is φ = 28368000.

The previous prime is 71631211. The next prime is 71631227. The reversal of 71631220 is 2213617.

It can be written as a sum of positive squares in 4 ways, for example, as 20394256 + 51236964 = 4516^2 + 7158^2 .

It is a junction number, because it is equal to n+sod(n) for n = 71631191 and 71631200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71631227) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15711 + ... + 19750.

It is an arithmetic number, because the mean of its divisors is an integer number (6329967).

Almost surely, 2^71631220 is an apocalyptic number.

It is an amenable number.

71631220 is an abundant number, since it is smaller than the sum of its proper divisors (80287988).

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

71631220 is a wasteful number, since it uses less digits than its factorization.

71631220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35571 (or 35569 counting only the distinct ones).

The product of its (nonzero) digits is 504, while the sum is 22.

The square root of 71631220 is about 8463.5229071587. The cubic root of 71631220 is about 415.3052769053.

Adding to 71631220 its reverse (2213617), we get a palindrome (73844837).

The spelling of 71631220 in words is "seventy-one million, six hundred thirty-one thousand, two hundred twenty".