21400071 has 16 divisors (see below), whose sum is σ = 35574528. Its totient is φ = 11116800.

The previous prime is 21400069. The next prime is 21400091. The reversal of 21400071 is 17000412.

It is not a de Polignac number, because 21400071 - 2¹ = 21400069 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21400071.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21400031) 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, 46090 + ... + 46551.

It is an arithmetic number, because the mean of its divisors is an integer number (2223408).

Almost surely, 2^21400071 is an apocalyptic number.

21400071 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

21400071 is a deficient number, since it is larger than the sum of its proper divisors (14174457).

21400071 is a wasteful number, since it uses less digits than its factorization.

21400071 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 92662.

The product of its (nonzero) digits is 56, while the sum is 15.

The square root of 21400071 is about 4626.0210764760. The cubic root of 21400071 is about 277.6334168939.

Adding to 21400071 its reverse (17000412), we get a palindrome (38400483).

The spelling of 21400071 in words is "twenty-one million, four hundred thousand, seventy-one".