21392742 has 32 divisors (see below), whose sum is σ = 49059072. Its totient is φ = 6092064.

The previous prime is 21392741. The next prime is 21392743. The reversal of 21392742 is 24729312.

It is an interprime number because it is at equal distance from previous prime (21392741) and next prime (21392743).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21392741) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16033 + ... + 17315.

It is an arithmetic number, because the mean of its divisors is an integer number (1533096).

Almost surely, 2^21392742 is an apocalyptic number.

21392742 is an abundant number, since it is smaller than the sum of its proper divisors (27666330).

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

21392742 is a wasteful number, since it uses less digits than its factorization.

21392742 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1692.

The product of its digits is 6048, while the sum is 30.

The square root of 21392742 is about 4625.2288592025. The cubic root of 21392742 is about 277.6017190607.

The spelling of 21392742 in words is "twenty-one million, three hundred ninety-two thousand, seven hundred forty-two".