21463690 has 16 divisors (see below), whose sum is σ = 40907592. Its totient is φ = 8080384.

The previous prime is 21463667. The next prime is 21463697. The reversal of 21463690 is 9636412.

It can be written as a sum of positive squares in 4 ways, for example, as 20802721 + 660969 = 4561^2 + 813^2 .

It is a super-2 number, since 2×21463690² = 921379976832200, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21463697) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 62959 + ... + 63298.

Almost surely, 2^21463690 is an apocalyptic number.

21463690 is a deficient number, since it is larger than the sum of its proper divisors (19443902).

21463690 is a wasteful number, since it uses less digits than its factorization.

21463690 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 126281.

The product of its (nonzero) digits is 7776, while the sum is 31.

The square root of 21463690 is about 4632.8921852338. The cubic root of 21463690 is about 277.9082646790.

The spelling of 21463690 in words is "twenty-one million, four hundred sixty-three thousand, six hundred ninety".