21780274 has 16 divisors (see below), whose sum is σ = 33596640. Its totient is φ = 10584000.

The previous prime is 21780257. The next prime is 21780329. The reversal of 21780274 is 47208712.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21082 + ... + 22090.

It is an arithmetic number, because the mean of its divisors is an integer number (2099790).

Almost surely, 2^21780274 is an apocalyptic number.

21780274 is a deficient number, since it is larger than the sum of its proper divisors (11816366).

21780274 is a wasteful number, since it uses less digits than its factorization.

21780274 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1305.

The product of its (nonzero) digits is 6272, while the sum is 31.

The square root of 21780274 is about 4666.9341113840. The cubic root of 21780274 is about 279.2679602519.

Adding to 21780274 its reverse (47208712), we get a palindrome (68988986).

The spelling of 21780274 in words is "twenty-one million, seven hundred eighty thousand, two hundred seventy-four".