1242720 has 72 divisors (see below), whose sum is σ = 4245696. Its totient is φ = 331008.

The previous prime is 1242643. The next prime is 1242739. The reversal of 1242720 is 272421.

It is a tau number, because it is divible by the number of its divisors (72).

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 = 1242693 and 1242702.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1009 + ... + 1871.

It is an arithmetic number, because the mean of its divisors is an integer number (58968).

2^1242720 is an apocalyptic number.

1242720 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 1242720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2122848).

1242720 is an abundant number, since it is smaller than the sum of its proper divisors (3002976).

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

1242720 is a wasteful number, since it uses less digits than its factorization.

1242720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 884 (or 873 counting only the distinct ones).

The product of its (nonzero) digits is 224, while the sum is 18.

The square root of 1242720 is about 1114.7735195994. The cubic root of 1242720 is about 107.5122034100.

Subtracting from 1242720 its reverse (272421), we obtain a cube (970299 = 99³).

The spelling of 1242720 in words is "one million, two hundred forty-two thousand, seven hundred twenty".