21451258 has 4 divisors (see below), whose sum is σ = 32176890. Its totient is φ = 10725628.

The previous prime is 21451237. The next prime is 21451277. The reversal of 21451258 is 85215412.

21451258 is nontrivially palindromic in base 7.

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

It can be written as a sum of positive squares in only one way, i.e., 10738729 + 10712529 = 3277^2 + 3273^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5362813 + ... + 5362816.

Almost surely, 2^21451258 is an apocalyptic number.

21451258 is a deficient number, since it is larger than the sum of its proper divisors (10725632).

21451258 is a wasteful number, since it uses less digits than its factorization.

21451258 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10725631.

The product of its digits is 3200, while the sum is 28.

The square root of 21451258 is about 4631.5502804137. The cubic root of 21451258 is about 277.8545984981.

It can be divided in two parts, 2145 and 1258, that added together give a triangular number (3403 = T₈₂).

The spelling of 21451258 in words is "twenty-one million, four hundred fifty-one thousand, two hundred fifty-eight".