1253279821 has 6 divisors (see below), whose sum is σ = 1310139950. Its totient is φ = 1198788888.

The previous prime is 1253279813. The next prime is 1253279893. The reversal of 1253279821 is 1289723521.

It can be written as a sum of positive squares in only one way, i.e., 918938596 + 334341225 = 30314^2 + 18285^2 .

It is not a de Polignac number, because 1253279821 - 2³ = 1253279813 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1253279801) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1184046 + ... + 1185103.

Almost surely, 2^1253279821 is an apocalyptic number.

It is an amenable number.

1253279821 is a deficient number, since it is larger than the sum of its proper divisors (56860129).

1253279821 is an equidigital number, since it uses as much as digits as its factorization.

1253279821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2369195 (or 2369172 counting only the distinct ones).

The product of its digits is 60480, while the sum is 40.

The square root of 1253279821 is about 35401.6923465532. The cubic root of 1253279821 is about 1078.1586768740.

The spelling of 1253279821 in words is "one billion, two hundred fifty-three million, two hundred seventy-nine thousand, eight hundred twenty-one".