21374661 has 32 divisors (see below), whose sum is σ = 37628928. Its totient is φ = 10448640.

The previous prime is 21374657. The next prime is 21374687. The reversal of 21374661 is 16647312.

It is not a de Polignac number, because 21374661 - 2² = 21374657 is a prime.

It is a super-2 number, since 2×21374661² = 913752265729842, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21374611) by changing a digit.

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 31 ways as a sum of consecutive naturals, for example, 1206 + ... + 6648.

It is an arithmetic number, because the mean of its divisors is an integer number (1175904).

Almost surely, 2^21374661 is an apocalyptic number.

21374661 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21374661 is a deficient number, since it is larger than the sum of its proper divisors (16254267).

21374661 is a wasteful number, since it uses less digits than its factorization.

21374661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5481.

The product of its digits is 6048, while the sum is 30.

The square root of 21374661 is about 4623.2738400402. The cubic root of 21374661 is about 277.5234879884.

The spelling of 21374661 in words is "twenty-one million, three hundred seventy-four thousand, six hundred sixty-one".