20190921 has 8 divisors (see below), whose sum is σ = 27377760. Its totient is φ = 13232352.

The previous prime is 20190913. The next prime is 20190943. The reversal of 20190921 is 12909102.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 20190921 - 2³ = 20190913 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20190891 and 20190900.

It is not an unprimeable number, because it can be changed into a prime (20190221) 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 7 ways as a sum of consecutive naturals, for example, 56860 + ... + 57213.

It is an arithmetic number, because the mean of its divisors is an integer number (3422220).

Almost surely, 2^20190921 is an apocalyptic number.

It is an amenable number.

20190921 is a deficient number, since it is larger than the sum of its proper divisors (7186839).

20190921 is a wasteful number, since it uses less digits than its factorization.

20190921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 114135.

The product of its (nonzero) digits is 324, while the sum is 24.

The square root of 20190921 is about 4493.4308718395. The cubic root of 20190921 is about 272.3027599425.

It can be divided in two parts, 201909 and 21, that added together give a triangular number (201930 = T₆₃₅).

The spelling of 20190921 in words is "twenty million, one hundred ninety thousand, nine hundred twenty-one".