637649220 has 192 divisors, whose sum is σ = 1997807616. Its totient is φ = 150958080.

The previous prime is 637649213. The next prime is 637649227. The reversal of 637649220 is 22946736.

It is an interprime number because it is at equal distance from previous prime (637649213) and next prime (637649227).

It is a Harshad number since it is a multiple of its sum of digits (39).

It is not an unprimeable number, because it can be changed into a prime (637649227) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 4061382 + ... + 4061538.

It is an arithmetic number, because the mean of its divisors is an integer number (10405248).

Almost surely, 2^637649220 is an apocalyptic number.

637649220 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 637649220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (998903808).

637649220 is an abundant number, since it is smaller than the sum of its proper divisors (1360158396).

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

637649220 is a wasteful number, since it uses less digits than its factorization.

637649220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 350 (or 348 counting only the distinct ones).

The product of its (nonzero) digits is 108864, while the sum is 39.

The square root of 637649220 is about 25251.7171693333. The cubic root of 637649220 is about 860.7174560993.

The spelling of 637649220 in words is "six hundred thirty-seven million, six hundred forty-nine thousand, two hundred twenty".