21149967 has 8 divisors (see below), whose sum is σ = 29109760. Its totient is φ = 13645080.

The previous prime is 21149951. The next prime is 21149969. The reversal of 21149967 is 76994112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21149967 - 2⁴ = 21149951 is a prime.

It is a super-2 number, since 2×21149967² = 894642208202178, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21149969) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 113617 + ... + 113802.

It is an arithmetic number, because the mean of its divisors is an integer number (3638720).

Almost surely, 2^21149967 is an apocalyptic number.

21149967 is a deficient number, since it is larger than the sum of its proper divisors (7959793).

21149967 is a wasteful number, since it uses less digits than its factorization.

21149967 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 227453.

The product of its digits is 27216, while the sum is 39.

The square root of 21149967 is about 4598.9093272210. The cubic root of 21149967 is about 276.5476026768.

The spelling of 21149967 in words is "twenty-one million, one hundred forty-nine thousand, nine hundred sixty-seven".