724978 has 16 divisors (see below), whose sum is σ = 1139544. Its totient is φ = 345600.

The previous prime is 724967. The next prime is 724991. The reversal of 724978 is 879427.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 717409 + 7569 = 847^2 + 87^2 .

It is a Harshad number since it is a multiple of its sum of digits (37).

It is an unprimeable number.

724978 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7128 + ... + 7228.

2⁷²⁴⁹⁷⁸ is an apocalyptic number.

724978 is a deficient number, since it is larger than the sum of its proper divisors (414566).

724978 is a wasteful number, since it uses less digits than its factorization.

724978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 237.

The product of its digits is 28224, while the sum is 37.

The square root of 724978 is about 851.4563993535. The cubic root of 724978 is about 89.8341802712.

Subtracting 724978 from its reverse (879427), we obtain a square (154449 = 393²).

It can be divided in two parts, 72 and 4978, that added together give a triangular number (5050 = T₁₀₀).

The spelling of 724978 in words is "seven hundred twenty-four thousand, nine hundred seventy-eight".