1921645605 has 32 divisors (see below), whose sum is σ = 3435965568. Its totient is φ = 908979200.

The previous prime is 1921645603. The next prime is 1921645613. The reversal of 1921645605 is 5065461291.

1921645605 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 1921645605 - 2¹ = 1921645603 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1921645603) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 135264 + ... + 148793.

It is an arithmetic number, because the mean of its divisors is an integer number (107373924).

Almost surely, 2^1921645605 is an apocalyptic number.

1921645605 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1921645605 is a deficient number, since it is larger than the sum of its proper divisors (1514319963).

1921645605 is a wasteful number, since it uses less digits than its factorization.

1921645605 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 284117.

The product of its (nonzero) digits is 64800, while the sum is 39.

The square root of 1921645605 is about 43836.5783906545. The cubic root of 1921645605 is about 1243.2479896874.

The spelling of 1921645605 in words is "one billion, nine hundred twenty-one million, six hundred forty-five thousand, six hundred five".