2151720 has 96 divisors (see below), whose sum is σ = 7207200. Its totient is φ = 556416.

The previous prime is 2151703. The next prime is 2151767. The reversal of 2151720 is 271512.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 2151693 and 2151702.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 15411 + ... + 15549.

It is an arithmetic number, because the mean of its divisors is an integer number (75075).

2^2151720 is an apocalyptic number.

2151720 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 2151720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3603600).

2151720 is an abundant number, since it is smaller than the sum of its proper divisors (5055480).

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

2151720 is a wasteful number, since it uses less digits than its factorization.

2151720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 199 (or 192 counting only the distinct ones).

The product of its (nonzero) digits is 140, while the sum is 18.

The square root of 2151720 is about 1466.8742277373. The cubic root of 2151720 is about 129.1006965703.

The spelling of 2151720 in words is "two million, one hundred fifty-one thousand, seven hundred twenty".