21971026 has 32 divisors (see below), whose sum is σ = 42882048. Its totient is φ = 8186640.

The previous prime is 21971023. The next prime is 21971057. The reversal of 21971026 is 62017912.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 21970985 and 21971003.

It is not an unprimeable number, because it can be changed into a prime (21971023) 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, 441 + ... + 6643.

It is an arithmetic number, because the mean of its divisors is an integer number (1340064).

Almost surely, 2^21971026 is an apocalyptic number.

21971026 is a deficient number, since it is larger than the sum of its proper divisors (20911022).

21971026 is a wasteful number, since it uses less digits than its factorization.

21971026 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6246.

The product of its (nonzero) digits is 1512, while the sum is 28.

The square root of 21971026 is about 4687.3261034411. The cubic root of 21971026 is about 280.0808694982.

Adding to 21971026 its reverse (62017912), we get a palindrome (83988938).

It can be divided in two parts, 2197 and 1026, that added together give a palindrome (3223).

The spelling of 21971026 in words is "twenty-one million, nine hundred seventy-one thousand, twenty-six".