164121720 has 128 divisors (see below), whose sum is σ = 572106240. Its totient is φ = 36887040.

The previous prime is 164121709. The next prime is 164121733. The reversal of 164121720 is 27121461.

It is a Cunningham number, because it is equal to 12811²-1.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 49639 + ... + 52841.

It is an arithmetic number, because the mean of its divisors is an integer number (4469580).

Almost surely, 2^164121720 is an apocalyptic number.

164121720 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 164121720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (286053120).

164121720 is an abundant number, since it is smaller than the sum of its proper divisors (407984520).

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

164121720 is a wasteful number, since it uses less digits than its factorization.

164121720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3285 (or 3281 counting only the distinct ones).

The product of its (nonzero) digits is 672, while the sum is 24.

The square root of 164121720 is about 12810.9999609710. Note that the first 4 decimals coincide. The cubic root of 164121720 is about 547.5057525302.

The spelling of 164121720 in words is "one hundred sixty-four million, one hundred twenty-one thousand, seven hundred twenty".