21131070 has 32 divisors (see below), whose sum is σ = 52087968. Its totient is φ = 5482368.

The previous prime is 21131069. The next prime is 21131081. The reversal of 21131070 is 7013112.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8409 + ... + 10628.

It is an arithmetic number, because the mean of its divisors is an integer number (1627749).

Almost surely, 2^21131070 is an apocalyptic number.

21131070 is an abundant number, since it is smaller than the sum of its proper divisors (30956898).

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

21131070 is a wasteful number, since it uses less digits than its factorization.

21131070 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19084.

The product of its (nonzero) digits is 42, while the sum is 15.

The square root of 21131070 is about 4596.8543592331. The cubic root of 21131070 is about 276.4652152002.

Adding to 21131070 its reverse (7013112), we get a palindrome (28144182).

The spelling of 21131070 in words is "twenty-one million, one hundred thirty-one thousand, seventy".