21539142 has 32 divisors (see below), whose sum is σ = 48204000. Its totient is φ = 7128864.

The previous prime is 21539137. The next prime is 21539149. The reversal of 21539142 is 24193512.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21539149) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6708 + ... + 9384.

It is an arithmetic number, because the mean of its divisors is an integer number (1506375).

Almost surely, 2^21539142 is an apocalyptic number.

21539142 is an abundant number, since it is smaller than the sum of its proper divisors (26664858).

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

21539142 is a wasteful number, since it uses less digits than its factorization.

21539142 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2837 (or 2831 counting only the distinct ones).

The product of its digits is 2160, while the sum is 27.

The square root of 21539142 is about 4641.0281188547. The cubic root of 21539142 is about 278.2335304584.

The spelling of 21539142 in words is "twenty-one million, five hundred thirty-nine thousand, one hundred forty-two".