21351004 has 6 divisors (see below), whose sum is σ = 37364264. Its totient is φ = 10675500.

The previous prime is 21350999. The next prime is 21351007. The reversal of 21351004 is 40015312.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21351007) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2668872 + ... + 2668879.

Almost surely, 2^21351004 is an apocalyptic number.

It is an amenable number.

21351004 is a deficient number, since it is larger than the sum of its proper divisors (16013260).

21351004 is a wasteful number, since it uses less digits than its factorization.

21351004 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5337755 (or 5337753 counting only the distinct ones).

The product of its (nonzero) digits is 120, while the sum is 16.

The square root of 21351004 is about 4620.7146633394. The cubic root of 21351004 is about 277.4210645818.

Adding to 21351004 its reverse (40015312), we get a palindrome (61366316).

The spelling of 21351004 in words is "twenty-one million, three hundred fifty-one thousand, four".