24997981 has 4 divisors (see below), whose sum is σ = 25142652. Its totient is φ = 24853312.

The previous prime is 24997961. The next prime is 24997993. The reversal of 24997981 is 18979942.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 9865881 + 15132100 = 3141^2 + 3890^2 .

It is a cyclic number.

It is not a de Polignac number, because 24997981 - 2⁵ = 24997949 is a prime.

It is a super-2 number, since 2×24997981² = 1249798108152722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (24997961) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 72076 + ... + 72421.

It is an arithmetic number, because the mean of its divisors is an integer number (6285663).

Almost surely, 2^24997981 is an apocalyptic number.

It is an amenable number.

24997981 is a deficient number, since it is larger than the sum of its proper divisors (144671).

24997981 is a wasteful number, since it uses less digits than its factorization.

24997981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 144670.

The product of its digits is 326592, while the sum is 49.

The square root of 24997981 is about 4999.7980959235. The cubic root of 24997981 is about 292.3939021536.

The spelling of 24997981 in words is "twenty-four million, nine hundred ninety-seven thousand, nine hundred eighty-one".