1921049729 has 4 divisors (see below), whose sum is σ = 1922341380. Its totient is φ = 1919758080.

The previous prime is 1921049693. The next prime is 1921049749. The reversal of 1921049729 is 9279401291.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9279401291 = 9413 ⋅985807.

It can be written as a sum of positive squares in 2 ways, for example, as 1337730625 + 583319104 = 36575^2 + 24152^2 .

It is a cyclic number.

It is not a de Polignac number, because 1921049729 - 2²⁸ = 1652614273 is a prime.

It is a super-2 number, since 2×1921049729² = 7380864122581946882, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1921049729.

It is not an unprimeable number, because it can be changed into a prime (1921049749) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 643592 + ... + 646569.

It is an arithmetic number, because the mean of its divisors is an integer number (480585345).

Almost surely, 2^1921049729 is an apocalyptic number.

It is an amenable number.

1921049729 is a deficient number, since it is larger than the sum of its proper divisors (1291651).

1921049729 is a wasteful number, since it uses less digits than its factorization.

1921049729 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1291650.

The product of its (nonzero) digits is 81648, while the sum is 44.

The square root of 1921049729 is about 43829.7813022150. The cubic root of 1921049729 is about 1243.1194716742.

The spelling of 1921049729 in words is "one billion, nine hundred twenty-one million, forty-nine thousand, seven hundred twenty-nine".