21501434 has 4 divisors (see below), whose sum is σ = 32252154. Its totient is φ = 10750716.

The previous prime is 21501401. The next prime is 21501451. The reversal of 21501434 is 43410512.

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

It can be written as a sum of positive squares in only one way, i.e., 15484225 + 6017209 = 3935^2 + 2453^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5375357 + ... + 5375360.

Almost surely, 2^21501434 is an apocalyptic number.

21501434 is a deficient number, since it is larger than the sum of its proper divisors (10750720).

21501434 is a wasteful number, since it uses less digits than its factorization.

21501434 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10750719.

The product of its (nonzero) digits is 480, while the sum is 20.

The square root of 21501434 is about 4636.9638773663. The cubic root of 21501434 is about 278.0710702824.

Adding to 21501434 its reverse (43410512), we get a palindrome (64911946).

The spelling of 21501434 in words is "twenty-one million, five hundred one thousand, four hundred thirty-four".