21533742 has 32 divisors (see below), whose sum is σ = 48051360. Its totient is φ = 7148160.

The previous prime is 21533737. The next prime is 21533789. The reversal of 21533742 is 24733512.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 15142 + ... + 16502.

It is an arithmetic number, because the mean of its divisors is an integer number (1501605).

Almost surely, 2^21533742 is an apocalyptic number.

21533742 is an abundant number, since it is smaller than the sum of its proper divisors (26517618).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21533742 is a wasteful number, since it uses less digits than its factorization.

21533742 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1665 (or 1659 counting only the distinct ones).

The product of its digits is 5040, while the sum is 27.

The square root of 21533742 is about 4640.4463147417. The cubic root of 21533742 is about 278.2102768760.

The spelling of 21533742 in words is "twenty-one million, five hundred thirty-three thousand, seven hundred forty-two".