21013074 has 32 divisors (see below), whose sum is σ = 47839680. Its totient is φ = 6832800.

The previous prime is 21013073. The next prime is 21013087. The reversal of 21013074 is 47031012.

21013074 = T₄₂₂ + T₄₂₃ + ... + T₅₈₅.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is not an unprimeable number, because it can be changed into a prime (21013073) 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, 2532 + ... + 6959.

It is an arithmetic number, because the mean of its divisors is an integer number (1494990).

Almost surely, 2^21013074 is an apocalyptic number.

21013074 is an abundant number, since it is smaller than the sum of its proper divisors (26826606).

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

21013074 is a wasteful number, since it uses less digits than its factorization.

21013074 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9543 (or 9537 counting only the distinct ones).

The product of its (nonzero) digits is 168, while the sum is 18.

The square root of 21013074 is about 4584.0019633504. The cubic root of 21013074 is about 275.9496600061.

Subtracting from 21013074 its sum of digits (18), we obtain a square (21013056 = 4584²).

Adding to 21013074 its reverse (47031012), we get a palindrome (68044086).

The spelling of 21013074 in words is "twenty-one million, thirteen thousand, seventy-four".