21501002 has 4 divisors (see below), whose sum is σ = 32251506. Its totient is φ = 10750500.

The previous prime is 21500953. The next prime is 21501023. The reversal of 21501002 is 20010512.

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., 15295921 + 6205081 = 3911^2 + 2491^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5375249 + ... + 5375252.

Almost surely, 2^21501002 is an apocalyptic number.

21501002 is a deficient number, since it is larger than the sum of its proper divisors (10750504).

21501002 is a wasteful number, since it uses less digits than its factorization.

21501002 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10750503.

The product of its (nonzero) digits is 20, while the sum is 11.

The square root of 21501002 is about 4636.9172949277. The cubic root of 21501002 is about 278.0692079647.

Adding to 21501002 its reverse (20010512), we get a palindrome (41511514).

The spelling of 21501002 in words is "twenty-one million, five hundred one thousand, two".