1921866772 has 24 divisors (see below), whose sum is σ = 3976277760. Its totient is φ = 795254880.

The previous prime is 1921866757. The next prime is 1921866773. The reversal of 1921866772 is 2776681291.

It is a hoax number, since the sum of its digits (49) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1921866773) 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, 1182604 + ... + 1184227.

It is an arithmetic number, because the mean of its divisors is an integer number (165678240).

Almost surely, 2^1921866772 is an apocalyptic number.

It is an amenable number.

1921866772 is an abundant number, since it is smaller than the sum of its proper divisors (2054410988).

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

1921866772 is a wasteful number, since it uses less digits than its factorization.

1921866772 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2366871 (or 2366869 counting only the distinct ones).

The product of its digits is 508032, while the sum is 49.

The square root of 1921866772 is about 43839.1009488105. The cubic root of 1921866772 is about 1243.2956840314.

The spelling of 1921866772 in words is "one billion, nine hundred twenty-one million, eight hundred sixty-six thousand, seven hundred seventy-two".