21115701 has 16 divisors (see below), whose sum is σ = 31579200. Its totient is φ = 13943664.

The previous prime is 21115657. The next prime is 21115723. The reversal of 21115701 is 10751112.

It is a happy number.

It is not a de Polignac number, because 21115701 - 2⁷ = 21115573 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21110701) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 766 + ... + 6543.

It is an arithmetic number, because the mean of its divisors is an integer number (1973700).

Almost surely, 2^21115701 is an apocalyptic number.

It is an amenable number.

21115701 is a deficient number, since it is larger than the sum of its proper divisors (10463499).

21115701 is a wasteful number, since it uses less digits than its factorization.

21115701 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7425 (or 7419 counting only the distinct ones).

The product of its (nonzero) digits is 70, while the sum is 18.

The square root of 21115701 is about 4595.1823685247. The cubic root of 21115701 is about 276.3981729344.

Adding to 21115701 its reverse (10751112), we get a palindrome (31866813).

The spelling of 21115701 in words is "twenty-one million, one hundred fifteen thousand, seven hundred one".