21353738 has 8 divisors (see below), whose sum is σ = 36606432. Its totient is φ = 9151596.

The previous prime is 21353737. The next prime is 21353767. The reversal of 21353738 is 83735312.

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

It is not an unprimeable number, because it can be changed into a prime (21353737) 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 3 ways as a sum of consecutive naturals, for example, 762620 + ... + 762647.

It is an arithmetic number, because the mean of its divisors is an integer number (4575804).

Almost surely, 2^21353738 is an apocalyptic number.

21353738 is a deficient number, since it is larger than the sum of its proper divisors (15252694).

21353738 is a wasteful number, since it uses less digits than its factorization.

21353738 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1525276.

The product of its digits is 15120, while the sum is 32.

The square root of 21353738 is about 4621.0104955518. The cubic root of 21353738 is about 277.4329053492.

It can be divided in two parts, 213537 and 38, that multiplied together give a triangular number (8114406 = T₄₀₂₈).

The spelling of 21353738 in words is "twenty-one million, three hundred fifty-three thousand, seven hundred thirty-eight".