21270402 has 24 divisors (see below), whose sum is σ = 47573760. Its totient is φ = 6861240.

The previous prime is 21270401. The next prime is 21270407. The reversal of 21270402 is 20407212.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21270401) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 18502 + ... + 19617.

It is an arithmetic number, because the mean of its divisors is an integer number (1982240).

Almost surely, 2^21270402 is an apocalyptic number.

21270402 is an abundant number, since it is smaller than the sum of its proper divisors (26303358).

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

21270402 is a wasteful number, since it uses less digits than its factorization.

21270402 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38158 (or 38155 counting only the distinct ones).

The product of its (nonzero) digits is 224, while the sum is 18.

The square root of 21270402 is about 4611.9846053516. The cubic root of 21270402 is about 277.0715277060.

Adding to 21270402 its reverse (20407212), we get a palindrome (41677614).

The spelling of 21270402 in words is "twenty-one million, two hundred seventy thousand, four hundred two".