21010104 has 40 divisors (see below), whose sum is σ = 58849560. Its totient is φ = 7003152.

The previous prime is 21010097. The next prime is 21010111. The reversal of 21010104 is 40101012.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21010097) and next prime (21010111).

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 15564 + ... + 16859.

It is an arithmetic number, because the mean of its divisors is an integer number (1471239).

Almost surely, 2^21010104 is an apocalyptic number.

21010104 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21010104 is an abundant number, since it is smaller than the sum of its proper divisors (37839456).

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

21010104 is a wasteful number, since it uses less digits than its factorization.

21010104 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32441 (or 32428 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

The square root of 21010104 is about 4583.6779991618. The cubic root of 21010104 is about 275.9366584322.

Adding to 21010104 its reverse (40101012), we get a palindrome (61111116).

The spelling of 21010104 in words is "twenty-one million, ten thousand, one hundred four".