249135021 has 14 divisors (see below), whose sum is σ = 373532750. Its totient is φ = 166089528.

The previous prime is 249134999. The next prime is 249135031. The reversal of 249135021 is 120531942.

It can be written as a sum of positive squares in only one way, i.e., 246929796 + 2205225 = 15714^2 + 1485^2 .

It is not a de Polignac number, because 249135021 - 2⁶ = 249134957 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (249135031) by changing a digit.

It is a polite number, since it can be written in 13 ways as a sum of consecutive naturals, for example, 170146 + ... + 171603.

Almost surely, 2^249135021 is an apocalyptic number.

It is an amenable number.

249135021 is a deficient number, since it is larger than the sum of its proper divisors (124397729).

249135021 is an frugal number, since it uses more digits than its factorization.

249135021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 341767 (or 341752 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 27.

The square root of 249135021 is about 15784.0115623374. The cubic root of 249135021 is about 629.2331485811.

Adding to 249135021 its reverse (120531942), we get a palindrome (369666963).

The spelling of 249135021 in words is "two hundred forty-nine million, one hundred thirty-five thousand, twenty-one".