1252643991 has 8 divisors (see below), whose sum is σ = 1715332464. Its totient is φ = 812525760.

The previous prime is 1252643933. The next prime is 1252644007. The reversal of 1252643991 is 1993462521.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1252643991 - 2¹⁰ = 1252642967 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1252643921) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5642430 + ... + 5642651.

It is an arithmetic number, because the mean of its divisors is an integer number (214416558).

Almost surely, 2^1252643991 is an apocalyptic number.

1252643991 is a deficient number, since it is larger than the sum of its proper divisors (462688473).

1252643991 is a wasteful number, since it uses less digits than its factorization.

1252643991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11285121.

The product of its digits is 116640, while the sum is 42.

The square root of 1252643991 is about 35392.7109868685. The cubic root of 1252643991 is about 1077.9763176002.

The spelling of 1252643991 in words is "one billion, two hundred fifty-two million, six hundred forty-three thousand, nine hundred ninety-one".