21237898 has 16 divisors (see below), whose sum is σ = 35064576. Its totient is φ = 9567040.

The previous prime is 21237847. The next prime is 21237899. The reversal of 21237898 is 89873212.

It is a super-2 number, since 2×21237898² = 902096622916808, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21237898.

It is not an unprimeable number, because it can be changed into a prime (21237899) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is an upside-down number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1786 + ... + 6757.

It is an arithmetic number, because the mean of its divisors is an integer number (2191536).

Almost surely, 2^21237898 is an apocalyptic number.

21237898 is a deficient number, since it is larger than the sum of its proper divisors (13826678).

21237898 is a wasteful number, since it uses less digits than its factorization.

21237898 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8669.

The product of its digits is 48384, while the sum is 40.

The square root of 21237898 is about 4608.4593955030. The cubic root of 21237898 is about 276.9303217201.

The spelling of 21237898 in words is "twenty-one million, two hundred thirty-seven thousand, eight hundred ninety-eight".