21770427 has 16 divisors (see below), whose sum is σ = 33946880. Its totient is φ = 12150432.

The previous prime is 21770423. The next prime is 21770429. The reversal of 21770427 is 72407712.

It is not a de Polignac number, because 21770427 - 2² = 21770423 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21770394 and 21770403.

It is not an unprimeable number, because it can be changed into a prime (21770423) 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, 11152 + ... + 12957.

It is an arithmetic number, because the mean of its divisors is an integer number (2121680).

Almost surely, 2^21770427 is an apocalyptic number.

21770427 is a deficient number, since it is larger than the sum of its proper divisors (12176453).

21770427 is a wasteful number, since it uses less digits than its factorization.

21770427 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24162.

The product of its (nonzero) digits is 5488, while the sum is 30.

The square root of 21770427 is about 4665.8790168627. The cubic root of 21770427 is about 279.2258676359.

The spelling of 21770427 in words is "twenty-one million, seven hundred seventy thousand, four hundred twenty-seven".