1251156542 has 4 divisors (see below), whose sum is σ = 1876734816. Its totient is φ = 625578270.

The previous prime is 1251156539. The next prime is 1251156547. The reversal of 1251156542 is 2456511521.

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

It is a junction number, because it is equal to n+sod(n) for n = 1251156499 and 1251156508.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1251156547) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 312789134 + ... + 312789137.

It is an arithmetic number, because the mean of its divisors is an integer number (469183704).

Almost surely, 2^1251156542 is an apocalyptic number.

1251156542 is a deficient number, since it is larger than the sum of its proper divisors (625578274).

1251156542 is an equidigital number, since it uses as much as digits as its factorization.

1251156542 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 625578273.

The product of its digits is 12000, while the sum is 32.

The square root of 1251156542 is about 35371.6912516210. The cubic root of 1251156542 is about 1077.5494685004.

The spelling of 1251156542 in words is "one billion, two hundred fifty-one million, one hundred fifty-six thousand, five hundred forty-two".