21531454 has 8 divisors (see below), whose sum is σ = 36911088. Its totient is φ = 9227760.

The previous prime is 21531443. The next prime is 21531479. The reversal of 21531454 is 45413512.

It is a happy number.

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

It is a super-2 number, since 2×21531454² = 927207022708232, 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 in 3 ways as a sum of consecutive naturals, for example, 768967 + ... + 768994.

It is an arithmetic number, because the mean of its divisors is an integer number (4613886).

Almost surely, 2^21531454 is an apocalyptic number.

21531454 is a deficient number, since it is larger than the sum of its proper divisors (15379634).

21531454 is a wasteful number, since it uses less digits than its factorization.

21531454 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1537970.

The product of its digits is 2400, while the sum is 25.

The square root of 21531454 is about 4640.1997801819. The cubic root of 21531454 is about 278.2004230745.

Adding to 21531454 its reverse (45413512), we get a palindrome (66944966).

The spelling of 21531454 in words is "twenty-one million, five hundred thirty-one thousand, four hundred fifty-four".