21091374 has 16 divisors (see below), whose sum is σ = 46869840. Its totient is φ = 7030440.

The previous prime is 21091361. The next prime is 21091409. The reversal of 21091374 is 47319012.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 195237 + ... + 195344.

It is an arithmetic number, because the mean of its divisors is an integer number (2929365).

Almost surely, 2^21091374 is an apocalyptic number.

21091374 is an abundant number, since it is smaller than the sum of its proper divisors (25778466).

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

21091374 is a wasteful number, since it uses less digits than its factorization.

21091374 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 390592 (or 390586 counting only the distinct ones).

The product of its (nonzero) digits is 1512, while the sum is 27.

The square root of 21091374 is about 4592.5345943172. The cubic root of 21091374 is about 276.2919877758.

The spelling of 21091374 in words is "twenty-one million, ninety-one thousand, three hundred seventy-four".