21351018 has 32 divisors (see below), whose sum is σ = 47577600. Its totient is φ = 6342336.

The previous prime is 21351017. The next prime is 21351053. The reversal of 21351018 is 81015312.

It is a junction number, because it is equal to n+sod(n) for n = 21350985 and 21351003.

It is not an unprimeable number, because it can be changed into a prime (21351013) 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, 2458 + ... + 6981.

It is an arithmetic number, because the mean of its divisors is an integer number (1486800).

Almost surely, 2^21351018 is an apocalyptic number.

21351018 is an abundant number, since it is smaller than the sum of its proper divisors (26226582).

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

21351018 is a wasteful number, since it uses less digits than its factorization.

21351018 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9486.

The product of its (nonzero) digits is 240, while the sum is 21.

The square root of 21351018 is about 4620.7161782564. The cubic root of 21351018 is about 277.4211252174.

The spelling of 21351018 in words is "twenty-one million, three hundred fifty-one thousand, eighteen".