201639720 has 128 divisors (see below), whose sum is σ = 647740800. Its totient is φ = 50036736.

The previous prime is 201639629. The next prime is 201639721. The reversal of 201639720 is 27936102.

201639720 = 3436² + 3437² + ... + 3452².

It is a Harshad number since it is a multiple of its sum of digits (30).

It is not an unprimeable number, because it can be changed into a prime (201639721) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 197371 + ... + 198389.

It is an arithmetic number, because the mean of its divisors is an integer number (5060475).

Almost surely, 2^201639720 is an apocalyptic number.

201639720 is a gapful number since it is divisible by the number (20) 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 201639720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (323870400).

201639720 is an abundant number, since it is smaller than the sum of its proper divisors (446101080).

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

201639720 is a wasteful number, since it uses less digits than its factorization.

201639720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1147 (or 1143 counting only the distinct ones).

The product of its (nonzero) digits is 4536, while the sum is 30.

The square root of 201639720 is about 14199.9901408416. The cubic root of 201639720 is about 586.3973899095.

The spelling of 201639720 in words is "two hundred one million, six hundred thirty-nine thousand, seven hundred twenty".