21307654 has 4 divisors (see below), whose sum is σ = 31961484. Its totient is φ = 10653826.

The previous prime is 21307609. The next prime is 21307669. The reversal of 21307654 is 45670312.

It is a semiprime because it is the product of two primes.

It is a super-2 number, since 2×21307654² = 908032237967432, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5326912 + ... + 5326915.

It is an arithmetic number, because the mean of its divisors is an integer number (7990371).

Almost surely, 2^21307654 is an apocalyptic number.

21307654 is a deficient number, since it is larger than the sum of its proper divisors (10653830).

21307654 is a wasteful number, since it uses less digits than its factorization.

21307654 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10653829.

The product of its (nonzero) digits is 5040, while the sum is 28.

The square root of 21307654 is about 4616.0214470906. The cubic root of 21307654 is about 277.2331834643.

Adding to 21307654 its reverse (45670312), we get a palindrome (66977966).

The spelling of 21307654 in words is "twenty-one million, three hundred seven thousand, six hundred fifty-four".