21455396 has 6 divisors (see below), whose sum is σ = 37546950. Its totient is φ = 10727696.

The previous prime is 21455393. The next prime is 21455429. The reversal of 21455396 is 69355412.

It can be written as a sum of positive squares in only one way, i.e., 21436900 + 18496 = 4630^2 + 136^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21455393) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2681921 + ... + 2681928.

It is an arithmetic number, because the mean of its divisors is an integer number (6257825).

Almost surely, 2^21455396 is an apocalyptic number.

It is an amenable number.

21455396 is a deficient number, since it is larger than the sum of its proper divisors (16091554).

21455396 is a wasteful number, since it uses less digits than its factorization.

21455396 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5363853 (or 5363851 counting only the distinct ones).

The product of its digits is 32400, while the sum is 35.

The square root of 21455396 is about 4631.9969775465. The cubic root of 21455396 is about 277.8724636260.

The spelling of 21455396 in words is "twenty-one million, four hundred fifty-five thousand, three hundred ninety-six".