1211779542 has 16 divisors (see below), whose sum is σ = 2429035200. Its totient is φ = 403013832.

The previous prime is 1211779531. The next prime is 1211779561. The reversal of 1211779542 is 2459771121.

It is a self number, because there is not a number n which added to its sum of digits gives 1211779542.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 225292 + ... + 230607.

It is an arithmetic number, because the mean of its divisors is an integer number (151814700).

Almost surely, 2^1211779542 is an apocalyptic number.

1211779542 is an abundant number, since it is smaller than the sum of its proper divisors (1217255658).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1211779542 is a wasteful number, since it uses less digits than its factorization.

1211779542 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 456347.

The product of its digits is 35280, while the sum is 39.

The square root of 1211779542 is about 34810.6239817674. The cubic root of 1211779542 is about 1066.1243731510.

The spelling of 1211779542 in words is "one billion, two hundred eleven million, seven hundred seventy-nine thousand, five hundred forty-two".