21690754 has 8 divisors (see below), whose sum is σ = 32592780. Its totient is φ = 10826496.

The previous prime is 21690743. The next prime is 21690787. The reversal of 21690754 is 45709612.

It can be written as a sum of positive squares in 2 ways, for example, as 18533025 + 3157729 = 4305^2 + 1777^2 .

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

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, 7959 + ... + 10330.

Almost surely, 2^21690754 is an apocalyptic number.

21690754 is a deficient number, since it is larger than the sum of its proper divisors (10902026).

21690754 is a wasteful number, since it uses less digits than its factorization.

21690754 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18884.

The product of its (nonzero) digits is 15120, while the sum is 34.

The square root of 21690754 is about 4657.3333571906. Note that the first 4 decimals coincide. The cubic root of 21690754 is about 278.8848246143.

The spelling of 21690754 in words is "twenty-one million, six hundred ninety thousand, seven hundred fifty-four".