21768994 has 32 divisors (see below), whose sum is σ = 37376640. Its totient is φ = 9432192.

The previous prime is 21768961. The next prime is 21768997. The reversal of 21768994 is 49986712.

It is a Harshad number since it is a multiple of its sum of digits (46).

It is not an unprimeable number, because it can be changed into a prime (21768997) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 34974 + ... + 35590.

It is an arithmetic number, because the mean of its divisors is an integer number (1168020).

Almost surely, 2^21768994 is an apocalyptic number.

21768994 is a deficient number, since it is larger than the sum of its proper divisors (15607646).

21768994 is a wasteful number, since it uses less digits than its factorization.

21768994 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 714.

The product of its digits is 217728, while the sum is 46.

The square root of 21768994 is about 4665.7254527029. The cubic root of 21768994 is about 279.2197409845.

The spelling of 21768994 in words is "twenty-one million, seven hundred sixty-eight thousand, nine hundred ninety-four".