252491981 has 16 divisors (see below), whose sum is σ = 296231040. Its totient is φ = 210693120.

The previous prime is 252491933. The next prime is 252491983. The reversal of 252491981 is 189194252.

It is a cyclic number.

It is not a de Polignac number, because 252491981 - 2¹⁰ = 252490957 is a prime.

It is a super-2 number, since 2×252491981² = 127504400938608722, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (41).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (252491983) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 266150 + ... + 267096.

It is an arithmetic number, because the mean of its divisors is an integer number (18514440).

Almost surely, 2^252491981 is an apocalyptic number.

It is an amenable number.

252491981 is a deficient number, since it is larger than the sum of its proper divisors (43739059).

252491981 is an equidigital number, since it uses as much as digits as its factorization.

252491981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1924.

The product of its digits is 51840, while the sum is 41.

The square root of 252491981 is about 15889.9962555062. The cubic root of 252491981 is about 632.0467413556.

The spelling of 252491981 in words is "two hundred fifty-two million, four hundred ninety-one thousand, nine hundred eighty-one".