21493742 has 4 divisors (see below), whose sum is σ = 32240616. Its totient is φ = 10746870.

The previous prime is 21493739. The next prime is 21493751. The reversal of 21493742 is 24739412.

It is a semiprime because it is the product of two primes.

It is a junction number, because it is equal to n+sod(n) for n = 21493699 and 21493708.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5373434 + ... + 5373437.

It is an arithmetic number, because the mean of its divisors is an integer number (8060154).

Almost surely, 2^21493742 is an apocalyptic number.

21493742 is a deficient number, since it is larger than the sum of its proper divisors (10746874).

21493742 is a wasteful number, since it uses less digits than its factorization.

21493742 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10746873.

The product of its digits is 12096, while the sum is 32.

The square root of 21493742 is about 4636.1343811413. The cubic root of 21493742 is about 278.0379069473.

The spelling of 21493742 in words is "twenty-one million, four hundred ninety-three thousand, seven hundred forty-two".