2151864 has 144 divisors (see below), whose sum is σ = 7261800. Its totient is φ = 570240.

The previous prime is 2151847. The next prime is 2151869. The reversal of 2151864 is 4681512.

2151864 = T₉₇ + T₉₈ + ... + T₂₃₉.

2151864 = 22³ + 23³ + ... + 54³.

Its product of digits (1920) is a multiple of the sum of its prime divisors (48).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2151869) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 113247 + ... + 113265.

2^2151864 is an apocalyptic number.

2151864 is a gapful number since it is divisible by the number (24) 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 2151864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3630900).

2151864 is an abundant number, since it is smaller than the sum of its proper divisors (5109936).

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

2151864 is a wasteful number, since it uses less digits than its factorization.

2151864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66 (or 48 counting only the distinct ones).

The product of its digits is 1920, while the sum is 27.

The square root of 2151864 is about 1466.9233108789. The cubic root of 2151864 is about 129.1035764502.

The spelling of 2151864 in words is "two million, one hundred fifty-one thousand, eight hundred sixty-four".