1391866772 has 18 divisors (see below), whose sum is σ = 2587477662. Its totient is φ = 654995584.

The previous prime is 1391866771. The next prime is 1391866841. The reversal of 1391866772 is 2776681931.

It can be written as a sum of positive squares in 3 ways, for example, as 213043216 + 1178823556 = 14596^2 + 34334^2 .

It is a super-2 number, since 2×1391866772² = 3874586221995399968, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 1391866772.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1391866771) 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, 600863 + ... + 603174.

It is an arithmetic number, because the mean of its divisors is an integer number (143748759).

Almost surely, 2^1391866772 is an apocalyptic number.

It is an amenable number.

1391866772 is a deficient number, since it is larger than the sum of its proper divisors (1195610890).

1391866772 is a wasteful number, since it uses less digits than its factorization.

1391866772 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1204075 (or 1204056 counting only the distinct ones).

The product of its digits is 762048, while the sum is 50.

The square root of 1391866772 is about 37307.7307270222. The cubic root of 1391866772 is about 1116.5184114852.

The spelling of 1391866772 in words is "one billion, three hundred ninety-one million, eight hundred sixty-six thousand, seven hundred seventy-two".