381651921 has 24 divisors (see below), whose sum is σ = 667090944. Its totient is φ = 205257600.

The previous prime is 381651911. The next prime is 381651931. The reversal of 381651921 is 129156183.

It is an interprime number because it is at equal distance from previous prime (381651911) and next prime (381651931).

It is not a de Polignac number, because 381651921 - 2⁵ = 381651889 is a prime.

It is not an unprimeable number, because it can be changed into a prime (381651901) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 177105 + ... + 179246.

It is an arithmetic number, because the mean of its divisors is an integer number (27795456).

Almost surely, 2^381651921 is an apocalyptic number.

It is an amenable number.

381651921 is a deficient number, since it is larger than the sum of its proper divisors (285439023).

381651921 is a wasteful number, since it uses less digits than its factorization.

381651921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 356381 (or 356378 counting only the distinct ones).

The product of its digits is 12960, while the sum is 36.

The square root of 381651921 is about 19535.9136208164. The cubic root of 381651921 is about 725.3636992464.

The spelling of 381651921 in words is "three hundred eighty-one million, six hundred fifty-one thousand, nine hundred twenty-one".