21492081 has 16 divisors (see below), whose sum is σ = 34289920. Its totient is φ = 13225680.

The previous prime is 21492067. The next prime is 21492151. The reversal of 21492081 is 18029412.

It is not a de Polignac number, because 21492081 - 2⁶ = 21492017 is a prime.

It is a super-2 number, since 2×21492081² = 923819091421122, which contains 22 as substring.

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

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21492011) 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, 30265 + ... + 30966.

It is an arithmetic number, because the mean of its divisors is an integer number (2143120).

Almost surely, 2^21492081 is an apocalyptic number.

It is an amenable number.

21492081 is a deficient number, since it is larger than the sum of its proper divisors (12797839).

21492081 is a wasteful number, since it uses less digits than its factorization.

21492081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 61253 (or 61247 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 27.

The square root of 21492081 is about 4635.9552413715. The cubic root of 21492081 is about 278.0307446632.

The spelling of 21492081 in words is "twenty-one million, four hundred ninety-two thousand, eighty-one".