19953921 has 16 divisors (see below), whose sum is σ = 29352960. Its totient is φ = 11978880.

The previous prime is 19953919. The next prime is 19953953. The reversal of 19953921 is 12935991.

It is not a de Polignac number, because 19953921 - 2¹ = 19953919 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a self number, because there is not a number n which added to its sum of digits gives 19953921.

It is not an unprimeable number, because it can be changed into a prime (19953821) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4641 + ... + 7838.

It is an arithmetic number, because the mean of its divisors is an integer number (1834560).

Almost surely, 2^19953921 is an apocalyptic number.

It is an amenable number.

19953921 is a deficient number, since it is larger than the sum of its proper divisors (9399039).

19953921 is a wasteful number, since it uses less digits than its factorization.

19953921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12536.

The product of its digits is 21870, while the sum is 39.

The square root of 19953921 is about 4466.9811953936. The cubic root of 19953921 is about 271.2331386094.

The spelling of 19953921 in words is "nineteen million, nine hundred fifty-three thousand, nine hundred twenty-one".