139640820 has 96 divisors (see below), whose sum is σ = 445132800. Its totient is φ = 32376960.

The previous prime is 139640803. The next prime is 139640827. The reversal of 139640820 is 28046931.

139640820 = 2453² + 2454² + ... + 2475².

It is a super-2 number, since 2×139640820² = 38999117220544800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (139640827) 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, 10581 + ... + 19779.

It is an arithmetic number, because the mean of its divisors is an integer number (4636800).

Almost surely, 2^139640820 is an apocalyptic number.

139640820 is a gapful number since it is divisible by the number (10) 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 139640820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (222566400).

139640820 is an abundant number, since it is smaller than the sum of its proper divisors (305491980).

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

139640820 is a wasteful number, since it uses less digits than its factorization.

139640820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9245 (or 9243 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 33.

The square root of 139640820 is about 11816.9716932893. The cubic root of 139640820 is about 518.8049727391.

The spelling of 139640820 in words is "one hundred thirty-nine million, six hundred forty thousand, eight hundred twenty".